Volume 28 (1874) (430 pages)

March 14, 1874.] MINING AND SCIENTIFIC PRESS. 167 Userue INFORMATION. Separaticn of Gold and Silver from Lead. Bat little is kuown, to those not engaged in the hnsiness, of the methods employed in this conntry for separating gold and silver from impnre lead; and we helieve tho following fscts, gathered hy our reporters, will he found of iuterest: Two grades of impnre lead are exported from Utah to the Eastern States for refining. The impurities arv gold aud silver, which communicate a superior harduess to the lead, and also increase its fnsibility. These iugredionts, however, however, do not exist iu sufticient proportion to warraut the application of the cupel process, or rather the loss of lead would be so eat us to make the operation too expensive. "he lowest grade contains 80 ounces of silver and 1 of gold to the ton; the other grade, kuown as the R. O. M. hullion, contains 120 ouucea of silverand 4 of gold per ton of bullion, Beside these oomponents, certain proportions of antimony and occasionally a trace of arsonic enter into the composition of the bullion. The bullion is first placed in kettles and melted to refine it. Iu this process the droas, which rises to the snrface of the metal during the melting, contaiua tho greater part of the impurities, such as antimony, hismuth, ete. This drosa is afterward refined separately in an appropriate furnace. This having heen removed, the melted metal is drawn off into a larger kettle. It is thence removed to other kettles, and a certain proportion of zinoadded, the quantity bearing a fixed ratio to the quantity of silver already in the metal. In the working ofeach sample of huilion a preliminary assay is necessary to determine the proportion of silver. When the metal is melted with the zinc, a slow fire is employed; and, os the process goes ou, an alloy of silver and zine rises to the surface. The latter is skimmed off, aud placed in a plumbago erncible, provided with a neck similar to a retort. The erncihle is then placed in one of Du Faur's furuaces, which is so arranged that it can he tilted by the aid ofa wheel attached to the furnace. The ziue is here distilled off, and condenses in the tuhe or neck, which is attaehed to the crncihle. A art of the zine is driven off as oxide, and this is lost, but about two-thirds of it sublimes in the neck of the crncible. When the tube is removed, the zinc is withdrawn therefrom, and used again in a similar operation. It will he rememhered that silver melts st about the same temperature at which zinc is volatilized. The metal remaining in the erncible consists of gold, silver, and lead, the latter in small quantity. This having been withdrawn, the precious metals are separated from the lead by enpellation, The resulting gold and silver are then run iuto ingots, and the silver removed by nitric acid, or by whatever method may he most convenient. In this mixture of gold and silver, gold forms from one-half to one and a half per ceut. Some idea of the magnitude of the operation may he formed from the following facts regarding a large establishment. They claim a weekly production of silver of about 12,000 ounces, and a proportionate quantity of lead. Generally, the procees returns about 89 per cent. of the lead which was in the bullion, at the commencement of the operation. They use cast iron kettles iu the process of separaHae ‘he silver from the lead by the aid of ziuc, each capable of holding two tons of bullion. Twelve of Dn Faur’s tilting furnaces are used, each cupola holding about 250 pounde of metal. Four refining furnaces are used, two capahle of a charge of 6 tone each, one of 12 tone, and one of 16 tons.—Iron Age. THE manner in which Hqueur bon-bons are made is extremely eimple. The engar preparation, reduced to a fine powder, ia apread over atray, and upou thia single drops of the liqueur are allowed to fall; the tray is then phaken, and the pulverized augar forma a-coating round the several dropa of filnid, which can be increased at will to any thickness. The manufacture of bou-hone ie carried on all over France, and in Paria alone there are nearly 200 ahopa devoted to it, employing over athousand haude. The men get froma frane and a half to eight franca a day, and the women from one to four france; while the amonnt of iudirect industry, euch as making boxee, packets, crackers, aud fancy goods, ia euormons. The last published atatietica show that the sweetmeat trade of France exceeda twelve million fraucs. Perhapa the greatest marvel is to find that the couutry itself expenda ten milliona of this sam.— The Engineer. Wary Auconon Cones Ratrugsnaxe Bitze.— The experimenta of Professor Binz, of Bonu, in regard to the effecte of alcohol ou animala, are exceedingly interestiug, in-ac-much aa he seems to have discovered the reaeona why alcoholio stimulante were eo useful in casee of snake poiaoning. He found that wheu decompoeed blood waeintroduced into tho veina of the living animal, all the symptoma of putrid feyer were shown, the temperature increasing until death eneued. Alcohol reduced.the heat, retarded the putrid procesa, increasing the action of the heart This seems to be precieely the effect of alcoholic stimulants, when administered in case of rattlesnake poisoning. Carbolic Acid. Carbolic acid, in some of the various forms in which it is offered tothe public, is ono of the most popular disinfectants, aud deservedly so. Forsimple disinfectiou, where the cause haa been removed, nothing is superior to the acid itself, either concentrated or in volution. It is extremely useful in sick roows and similar placee for cleansing the vessels which have heen used, and a swall quantity of it added to the water in which the elothes are washed, will effectually destroy al. germs of disease whioh muy he present. For disinfecting tho air of a mee room a few drops may be put npona hot shovel or stove-lid, or any article that will retain its heat forsome time. It has the advantage that it does not injure clothing or metal articles with which the vapor comes in contaet. It shonld he used with care, however, as the liquid itself is a violent poisou, cven in small doses. In many cases, howover, somcthing more convenient of manipulation is wanted thau the liqnid. Thisis furuished by several different compounds, The so-called ‘metropolitan disinfectant’’ isa mixturo of scsquioxide of iron aud carbolic acid. Tho iron destroys the organic matter with which it comesin contact, aud the earbolic acid is slowly given off and acts in purifying the air. Another compouud is tho ‘“‘Eyyptian powder,’’ which contaius common clay as a basis. Still another, and one which has proved of great uso, is carbolate of lime. Carholio acid has the property of combiniug with alkalies and alkaline earths without having its active qualities destroyed, as these compounds sre very unstable, and are decomposed by the weskest acids. The earbolate of lime is a dry powder, with generally a rose tinge, and smelis somewhat like ordinary coal-tar, The lime in it acts upon, and soon destroys any organic matter with which it may come iu contaet, the carholic acid heing set free. It is extremely conveuient and useful in all places where decaying matter is found. A little of it seattered two or three times a week around a swill-pail or other offeusive object, keep it perfeotly sweet, and will also drive away all the fliee from the vicinity—Journal of Chemistry. ALcoHoL Frost Sawpust.—The cheapest material of which to make brandy, whisky, and alcohol is at present sawdust. We mentioned before that sugar is now made of it, and a direct consequence of this is that this sugar, by proper fermentation and distillation, can be made into alcohol, and this again hy rectification and flavoring, into any of the mixtures kuown as gin, whisky, rum, arrack, cognac, bandy, ete. This manufacture of alcohol from sawdust is now carried on in Sweden very economically and ou an extensivescale. We rejoice, hecanse if the great staples, such as corn, wheat, rye, barley, eto., are used for this purpose, there is a destruction of material valuable for food; a breaking down of more complex valuable organic compounds into simpler ones, and if these same simpler compounds can ss well be obtaiued from sawdust, which ueither auimal nor man can eat, there is a great saving in valuable material. The only objection thus far, is that iu this operation a portion of the product is not the ordinary ethylic alcohol, but methylic alcohol, or wood spirits, which is less palstahle and more unwholesome than ordiuary alcohol; but that there is no doubt that improvements in this respect will soon be made, if this ie not already the case, aud that, as people must have alcohol, it will in the future not he produced at the cost of the deetruction of a great portion of the staples of food otherwiee adapted for the nourishment of millions, and which now are continually being deatroyed by the dietillers over all the world.— Manufacturer and Builder. To IncrEASE THE ADHESIVENESS oF Gua Anapio,—Conceutrated solutions of gum arabic as a mucilage, says Hager, poseoss the disagreeable property, when spread upon printing or other paper not etrongly sized, to penetrate them to transparency, and in apite of thia not making them adhere to other paper. Paper oannot be attached to common pasteboard, nor wood to wood. Paper pasted with mucilage on metallic aurfaces uanally falla off eoon. The use of gum as cement for glasa, porcelain, or earthenware, etc., is entirely imposaible. All these disadvautages of mucilage are remedied, when an aqueous solution of sulphate of aluminum ieadded. For 250 grammea of the concentrated gum eolutiou (prepared with 2 parta of gum and 5 of water,) two grammes of cryet. aluminum sulphate will suffice. Thia salt is dissolved in ten times its quantity of water, and mixed directly with the mucilage, which in thie coudition truly deserves the name of vegetable glue, Solution of alam aerves the same purpose, but far less efficiently. TRANSFERRING Pictures To Guass.—Coat the glasa with a varnish of balsam of fir iu turpentine, then press the engraving ouemoothly and evenly, being careful to remove all air hubbles. Let it atand for 24 hours, then dampen the hack enfficiently to allow the paper to be rubbed off by the forefinger, rubbing it till a mere film Jadot ou the glass, then varnish agaiu.—sSc. m, ANOTHER proceas for preserving meat ia annouuced. By thie method the auimal is killed by felling, and immediately skinned and cleaued. It is then glazed over with a preparatiou of eugar and alcohol and placed in a hed of fat. The case is exhausted of air and soldered up. Goopo Hearty. The Causes of Decay of Teeth. It has been charged against our brethron of tho dental spocialty, says the Lancet, that they are wofully at fanlt in regard to knowledgo of the commonest of all things—caries of the teeth. That they extract teeth with skill, and stop them with even moro skill, and in a nobly conservative spirit, is admitted; hut the causes of deeny inthe teeth have remained ohscure. The investigatious of Leher and Rottenstein into this subject have at least the charm of pointing to detinite conolusions. They admit, of course, that there are differences of tceth, constitutional aud connected with race, makiug teeth more or less resistant to the great influences which determine decay. These are not, aecording to these authors, internal and vital so much aa external aud chemical. The process of decay hegins from the surface, aud if it cau be controlled or arrested at the surface, it is entirely controlled. Tho great canses of caries are two, namely, acids and a certain fuugns found abundantly iu the month, leptothrix buecalis. This latter agent is eharacterized hy certain microscopic appearances aud by its reaction with iodine and acids, whieh give to the elements of lepfothrix a heautiful violet tinge, Uuder the microspope the fungus appears as a gray, finely-grauular mass or matrix, with filaments delicate and stiff, which erect themselves ahove the surface of this granular substanoe so as to rossmbhle an uneven turf. The fungus attaiue its greatest size in the interstices of the teeth, No one can deuy now-a-days the action of acids on the teeth, even weak acids, in dissolving the salts of the enamel and the detine, All acids, both mineral and vegetable, act promptly on the teeth, Varions experimente as to the action of acids on dental tissues are given, making the enamel, naturally transparent, first white, opaque and milky, and, iu a more advanced state, chalky, and then the dentine more transparent and softer, so as to be cut with aknife. The acids which may actually effect the first changes in the production of caries are such as are taken with food, or in medicines, or sueh ae are formed in the mouth itself hy some abnormality iu our secretions, which should he alkaline, or by an acid fermentation of particles of food. But acids alone will not account for all the pheuomeua of caries in the teeth. They play a primary and principal part, making the teeth porous and soft. In this state, the tissues having lost their normal consisteucy, fungi penetrate hoth the canalicnliof the enamel aud of the dentine, snd by their proliferation produce softeniug and destructive effects much more rapidly than the action of acids alone is able to accomplish. It is not pleasaut to think that fungi exist in the mouth of all but the very clesuest of people. Bowditch, in examining forty persous of different professions, and living different kinds of life, found in almost all vegetable and auimal parasites. The parasites were numerous in proportion to the neglect of cleauliness. The means ordinarily employed to clean the teeth had no effect on the parasites, while soapy water appeared to destroy them. If this bea true version of the canses of caries—the actiou of acids, supplemented by the action of fungi—then it follows that the great means of preserving teeth is to preserve the most scrupuloue cleanliness of the mouth and teeth, and to give to the rinsing liquide a slightly alkaline chsracter, which ie done by the admixture of a little soap. This is not so pleacanta dentifrice as some, but it ie effective and scientific. Acids not only dieeolve the ealts of the teeth, but favor the inerease of the fungi of the mouth. No increase of fungi and no action ou the deutsl issues occurs in solutions slightly alksline, as of a weak solution of soap. The good effects of stopping -teeth, in the light of these experiments, are intelligihle. The penetration of acids and fungi is prevented. HaTIne WHEN S1ox.—lIt is the custom among acertain class of people, when a member of the family falls sick, to begin at once to ask, ‘Now what can yon eat?’’ Tvery one haa heard of the old atory of the man who always ate eighteen apple dumplinge wheu he was sick. On oue occasion when he was engaged upon the eighteenth, his little son said, ‘Pa, give me a piece,’’ “No, no, my son, replied the father, ‘go away; pais sick.’ When a young man has aurfeited in eeaeon and ont of season, nntil exhausted nature gives way, and a fever is coming on, the good mother ia iu trouble. She anxionsly inquirea, ‘Now, John, what can you eat? Yon must eat something! Poople can’t live withont food!” Then comes toast and tea, etc. The stomach is exhausted, and no more needs stimulating or food than a jaded horse needs the whip. What is needed is rest. Nine-tenthe of the acute diseases might be prevented by a few daye’ atarvation when the first indications appear, I dou’t mean complete abstinence in every case, but perhaps a piece of coarse hread, with cold water for drink. If auch a policy were generally adopted, whatruin would overtake the medical profession. How many physicians wonld lack for patients.— Hearth and Home. In the hydropathic treatment, drinking cold water immediately after rieiug, provided that breakfast be not taken for atleast half an hour, is prescrihed. The explanation given is that the internal donche acta upou the stomach as @ tonic, in thesame manner as cold applications externally, upon the skin, Action of Tobacco Smoke. According to Messrs, Yoh] and Bulemherg, the amount of nicotine in snuff and tohaeco for chewing is so miunte that nothing like nicotine-poisoniug can result from their use. The action of tohacco-smoke and tohaceo-jnice is uot due to nicotine, for it contains nove, hut to pyridine, picoline, collediue, aud other bases, forming a homologons series, which are produced during the comhnstion of the tohacco. The reason why strouger tohacco can ho smoked in a cigar than iu a pipe is, that in the pipe a large quantity of pyridino is formed, which ie vary volatile and stupefying; while ina cigar little pyridine and mueh colledine are formed. The nnpleasant symptoms expericnced hy persons just beginning to smoke, or who smoke to excess, as well as the.poisouous effect of tobaeco-juice, are not duo to nicotine, hut to the pyradiue and picoliue hases; aud they have probably heen attributed to nicotine because these bases, especially thoso having a high hoilingpoint, greatiy resemble nicotine both in smetl and in physiological action, producing coutraetion of the pupil, difficult respiration, convulsions and death. They do uot act so quickly when injeotcd under the skiu as when takeninto the stomach, and their action is less rapid than that of uicotine, Other plants which are sometimes used for smokiug, though they coutain no nicotiue, such as dandelion, willow wood and stramonium, yield pyridine hases, whose action are very like those from tobacco, though rather weaker, Pure picoline from Boghead coal had a similar action; and its vapor was poisonous, probucing irritation of the respiratory passages, shght convulsions, aud death. None of theso, except the bases from willow wood, produced contraction of the papil. The authors consider that the effects produced by opiumsmoking are not due to the alksloids iu the opium, hut to the bases formed dnring its combustion; and that tbe difference hetween it and tobacco is owing to different hascs heing formed hy their comhustion.—Arch. Pharm. and Chem. Color Blindness. The derivation of the designation of an affection of the eyes very commouly kuowu as Daltonism (color bliudness) is, as msny of our readers are doubtless aware, from the name of the great philosopher, the propounder of the atomic theory, who was attacked by it. Properly speaking it is simply iucapacity on the part of certain people to judge of color, or more accurately, of certain colors. Dr. Fayre has communicated to the Congress at Lyons the result of the researches, which, as chief physician of the Paris aud Lyons railway company, he has made on the subject, the object heiug to determine what influence this disease or affection may have on the general ssfety of travelers, According to this report, amoug 1196 different individuals examiued from 1864 to 1868, thirteeu cases of red-color blindness aud one of green were found. Again, among 728 subjects examiued between 1872 and 1873 he testifies to forty-two of color blinduess more or less developed. He further estimates the number of people in France sufferiug from this malady at nearly a million, and gives, as the most common causes of it, wounds, typhoid fever, syphilis, ete. The danger of such a disease existing, aud possible iu some instences without the knowledge of the subject or of his employers, is oue whieh deserves attention, for although we cannot point oureelves to any instances iu which errors have been made through it, neverthelese, Dr. Favre, as we understand him, is able to do s0, and we quite agree with him, wheu he saye thst the only effeetual preventive of the dangers which may possibly accrue fromsuch a malady isa periodical optical iuspectiou of all men who have to deal with colored signals, a mistake in the use of which might lead to such disastrous results. We recommend juquiry on this enbject to locomotive superintendents aud traffic mansgers.—The Enyineer. SuNsHINE anD SteeP.—Sleepless persons should court the sun. The very worst soporific ia laudanum, and the very best, sunshiue. Therefore it is very plain that poor sleepers should pass as wany hours aa possible iu the snnshiue, and as few aa possible in the shade. Many women are martyrs, and yet they donot knowit. They shut the sunshine out of their housea and their hearts, they wear yejls, they carry parasols, they do all poeeihle to keep off the most potent influence which is intended to give them strength and beauty, and cheerfulness. It is not time to change'all this, aud so get color aud roses in our pale cheeks, strength in onr weak backs, aud courage in onr timid eonls? The women of America are pale and delicate, but with the aid of eunlight they may be hloomiug and strong.— Home and Health, Borax ror Coups.—A writer in The Medical Record cites a number of cases in which horax has proved a most efleciive remedy in certain forms of colda. He statea that, in sudden hoarsenese or loss of voice in public speakers or singere, from colds, relief for an hour or s0, as by magic, may be often obtaiued by slowly dissolviug, and partially swallowing, a lump of horax, the aize of a garden pea, or about three or four grains, held in the mouth for ten minutea before apeaking or singing. This produces a profuse secretion of saliva,.or ‘‘watering”’ of the mouth aud throat, prohably restoriug the voice or tone to the dried vocal cords, just as wettiug brings hack the missing uotes to a flute when it is too dry.

March 14, 1874.] MINING AND SCIENTIFIC PRESS. 167 Userue INFORMATION. Separaticn of Gold and Silver from Lead. Bat little is kuown, to those not engaged in the hnsiness, of the methods employed in this conntry for separating gold and silver from impnre lead; and we helieve tho following fscts, gathered hy our reporters, will he found of iuterest: Two grades of impnre lead are exported from Utah to the Eastern States for refining. The impurities arv gold aud silver, which communicate a superior harduess to the lead, and also increase its fnsibility. These iugredionts, however, however, do not exist iu sufticient proportion to warraut the application of the cupel process, or rather the loss of lead would be so eat us to make the operation too expensive. "he lowest grade contains 80 ounces of silver and 1 of gold to the ton; the other grade, kuown as the R. O. M. hullion, contains 120 ouucea of silverand 4 of gold per ton of bullion, Beside these oomponents, certain proportions of antimony and occasionally a trace of arsonic enter into the composition of the bullion. The bullion is first placed in kettles and melted to refine it. Iu this process the droas, which rises to the snrface of the metal during the melting, contaiua tho greater part of the impurities, such as antimony, hismuth, ete. This drosa is afterward refined separately in an appropriate furnace. This having heen removed, the melted metal is drawn off into a larger kettle. It is thence removed to other kettles, and a certain proportion of zinoadded, the quantity bearing a fixed ratio to the quantity of silver already in the metal. In the working ofeach sample of huilion a preliminary assay is necessary to determine the proportion of silver. When the metal is melted with the zinc, a slow fire is employed; and, os the process goes ou, an alloy of silver and zine rises to the surface. The latter is skimmed off, aud placed in a plumbago erncible, provided with a neck similar to a retort. The erncihle is then placed in one of Du Faur's furuaces, which is so arranged that it can he tilted by the aid ofa wheel attached to the furnace. The ziue is here distilled off, and condenses in the tuhe or neck, which is attaehed to the crncihle. A art of the zine is driven off as oxide, and this is lost, but about two-thirds of it sublimes in the neck of the crncible. When the tube is removed, the zinc is withdrawn therefrom, and used again in a similar operation. It will he rememhered that silver melts st about the same temperature at which zinc is volatilized. The metal remaining in the erncible consists of gold, silver, and lead, the latter in small quantity. This having been withdrawn, the precious metals are separated from the lead by enpellation, The resulting gold and silver are then run iuto ingots, and the silver removed by nitric acid, or by whatever method may he most convenient. In this mixture of gold and silver, gold forms from one-half to one and a half per ceut. Some idea of the magnitude of the operation may he formed from the following facts regarding a large establishment. They claim a weekly production of silver of about 12,000 ounces, and a proportionate quantity of lead. Generally, the procees returns about 89 per cent. of the lead which was in the bullion, at the commencement of the operation. They use cast iron kettles iu the process of separaHae ‘he silver from the lead by the aid of ziuc, each capable of holding two tons of bullion. Twelve of Dn Faur’s tilting furnaces are used, each cupola holding about 250 pounde of metal. Four refining furnaces are used, two capahle of a charge of 6 tone each, one of 12 tone, and one of 16 tons.—Iron Age. THE manner in which Hqueur bon-bons are made is extremely eimple. The engar preparation, reduced to a fine powder, ia apread over atray, and upou thia single drops of the liqueur are allowed to fall; the tray is then phaken, and the pulverized augar forma a-coating round the several dropa of filnid, which can be increased at will to any thickness. The manufacture of bou-hone ie carried on all over France, and in Paria alone there are nearly 200 ahopa devoted to it, employing over athousand haude. The men get froma frane and a half to eight franca a day, and the women from one to four france; while the amonnt of iudirect industry, euch as making boxee, packets, crackers, aud fancy goods, ia euormons. The last published atatietica show that the sweetmeat trade of France exceeda twelve million fraucs. Perhapa the greatest marvel is to find that the couutry itself expenda ten milliona of this sam.— The Engineer. Wary Auconon Cones Ratrugsnaxe Bitze.— The experimenta of Professor Binz, of Bonu, in regard to the effecte of alcohol ou animala, are exceedingly interestiug, in-ac-much aa he seems to have discovered the reaeona why alcoholio stimulante were eo useful in casee of snake poiaoning. He found that wheu decompoeed blood waeintroduced into tho veina of the living animal, all the symptoma of putrid feyer were shown, the temperature increasing until death eneued. Alcohol reduced.the heat, retarded the putrid procesa, increasing the action of the heart This seems to be precieely the effect of alcoholic stimulants, when administered in case of rattlesnake poisoning. Carbolic Acid. Carbolic acid, in some of the various forms in which it is offered tothe public, is ono of the most popular disinfectants, aud deservedly so. Forsimple disinfectiou, where the cause haa been removed, nothing is superior to the acid itself, either concentrated or in volution. It is extremely useful in sick roows and similar placee for cleansing the vessels which have heen used, and a swall quantity of it added to the water in which the elothes are washed, will effectually destroy al. germs of disease whioh muy he present. For disinfecting tho air of a mee room a few drops may be put npona hot shovel or stove-lid, or any article that will retain its heat forsome time. It has the advantage that it does not injure clothing or metal articles with which the vapor comes in contaet. It shonld he used with care, however, as the liquid itself is a violent poisou, cven in small doses. In many cases, howover, somcthing more convenient of manipulation is wanted thau the liqnid. Thisis furuished by several different compounds, The so-called ‘metropolitan disinfectant’’ isa mixturo of scsquioxide of iron aud carbolic acid. Tho iron destroys the organic matter with which it comesin contact, aud the earbolic acid is slowly given off and acts in purifying the air. Another compouud is tho ‘“‘Eyyptian powder,’’ which contaius common clay as a basis. Still another, and one which has proved of great uso, is carbolate of lime. Carholio acid has the property of combiniug with alkalies and alkaline earths without having its active qualities destroyed, as these compounds sre very unstable, and are decomposed by the weskest acids. The earbolate of lime is a dry powder, with generally a rose tinge, and smelis somewhat like ordinary coal-tar, The lime in it acts upon, and soon destroys any organic matter with which it may come iu contaet, the carholic acid heing set free. It is extremely conveuient and useful in all places where decaying matter is found. A little of it seattered two or three times a week around a swill-pail or other offeusive object, keep it perfeotly sweet, and will also drive away all the fliee from the vicinity—Journal of Chemistry. ALcoHoL Frost Sawpust.—The cheapest material of which to make brandy, whisky, and alcohol is at present sawdust. We mentioned before that sugar is now made of it, and a direct consequence of this is that this sugar, by proper fermentation and distillation, can be made into alcohol, and this again hy rectification and flavoring, into any of the mixtures kuown as gin, whisky, rum, arrack, cognac, bandy, ete. This manufacture of alcohol from sawdust is now carried on in Sweden very economically and ou an extensivescale. We rejoice, hecanse if the great staples, such as corn, wheat, rye, barley, eto., are used for this purpose, there is a destruction of material valuable for food; a breaking down of more complex valuable organic compounds into simpler ones, and if these same simpler compounds can ss well be obtaiued from sawdust, which ueither auimal nor man can eat, there is a great saving in valuable material. The only objection thus far, is that iu this operation a portion of the product is not the ordinary ethylic alcohol, but methylic alcohol, or wood spirits, which is less palstahle and more unwholesome than ordiuary alcohol; but that there is no doubt that improvements in this respect will soon be made, if this ie not already the case, aud that, as people must have alcohol, it will in the future not he produced at the cost of the deetruction of a great portion of the staples of food otherwiee adapted for the nourishment of millions, and which now are continually being deatroyed by the dietillers over all the world.— Manufacturer and Builder. To IncrEASE THE ADHESIVENESS oF Gua Anapio,—Conceutrated solutions of gum arabic as a mucilage, says Hager, poseoss the disagreeable property, when spread upon printing or other paper not etrongly sized, to penetrate them to transparency, and in apite of thia not making them adhere to other paper. Paper oannot be attached to common pasteboard, nor wood to wood. Paper pasted with mucilage on metallic aurfaces uanally falla off eoon. The use of gum as cement for glasa, porcelain, or earthenware, etc., is entirely imposaible. All these disadvautages of mucilage are remedied, when an aqueous solution of sulphate of aluminum ieadded. For 250 grammea of the concentrated gum eolutiou (prepared with 2 parta of gum and 5 of water,) two grammes of cryet. aluminum sulphate will suffice. Thia salt is dissolved in ten times its quantity of water, and mixed directly with the mucilage, which in thie coudition truly deserves the name of vegetable glue, Solution of alam aerves the same purpose, but far less efficiently. TRANSFERRING Pictures To Guass.—Coat the glasa with a varnish of balsam of fir iu turpentine, then press the engraving ouemoothly and evenly, being careful to remove all air hubbles. Let it atand for 24 hours, then dampen the hack enfficiently to allow the paper to be rubbed off by the forefinger, rubbing it till a mere film Jadot ou the glass, then varnish agaiu.—sSc.

m, ANOTHER proceas for preserving meat ia annouuced. By thie method the auimal is killed by felling, and immediately skinned and cleaued. It is then glazed over with a preparatiou of eugar and alcohol and placed in a hed of fat. The case is exhausted of air and soldered up. Goopo Hearty. The Causes of Decay of Teeth. It has been charged against our brethron of tho dental spocialty, says the Lancet, that they are wofully at fanlt in regard to knowledgo of the commonest of all things—caries of the teeth. That they extract teeth with skill, and stop them with even moro skill, and in a nobly conservative spirit, is admitted; hut the causes of deeny inthe teeth have remained ohscure. The investigatious of Leher and Rottenstein into this subject have at least the charm of pointing to detinite conolusions. They admit, of course, that there are differences of tceth, constitutional aud connected with race, makiug teeth more or less resistant to the great influences which determine decay. These are not, aecording to these authors, internal and vital so much aa external aud chemical. The process of decay hegins from the surface, aud if it cau be controlled or arrested at the surface, it is entirely controlled. Tho great canses of caries are two, namely, acids and a certain fuugns found abundantly iu the month, leptothrix buecalis. This latter agent is eharacterized hy certain microscopic appearances aud by its reaction with iodine and acids, whieh give to the elements of lepfothrix a heautiful violet tinge, Uuder the microspope the fungus appears as a gray, finely-grauular mass or matrix, with filaments delicate and stiff, which erect themselves ahove the surface of this granular substanoe so as to rossmbhle an uneven turf. The fungus attaiue its greatest size in the interstices of the teeth, No one can deuy now-a-days the action of acids on the teeth, even weak acids, in dissolving the salts of the enamel and the detine, All acids, both mineral and vegetable, act promptly on the teeth, Varions experimente as to the action of acids on dental tissues are given, making the enamel, naturally transparent, first white, opaque and milky, and, iu a more advanced state, chalky, and then the dentine more transparent and softer, so as to be cut with aknife. The acids which may actually effect the first changes in the production of caries are such as are taken with food, or in medicines, or sueh ae are formed in the mouth itself hy some abnormality iu our secretions, which should he alkaline, or by an acid fermentation of particles of food. But acids alone will not account for all the pheuomeua of caries in the teeth. They play a primary and principal part, making the teeth porous and soft. In this state, the tissues having lost their normal consisteucy, fungi penetrate hoth the canalicnliof the enamel aud of the dentine, snd by their proliferation produce softeniug and destructive effects much more rapidly than the action of acids alone is able to accomplish. It is not pleasaut to think that fungi exist in the mouth of all but the very clesuest of people. Bowditch, in examining forty persous of different professions, and living different kinds of life, found in almost all vegetable and auimal parasites. The parasites were numerous in proportion to the neglect of cleauliness. The means ordinarily employed to clean the teeth had no effect on the parasites, while soapy water appeared to destroy them. If this bea true version of the canses of caries—the actiou of acids, supplemented by the action of fungi—then it follows that the great means of preserving teeth is to preserve the most scrupuloue cleanliness of the mouth and teeth, and to give to the rinsing liquide a slightly alkaline chsracter, which ie done by the admixture of a little soap. This is not so pleacanta dentifrice as some, but it ie effective and scientific. Acids not only dieeolve the ealts of the teeth, but favor the inerease of the fungi of the mouth. No increase of fungi and no action ou the deutsl issues occurs in solutions slightly alksline, as of a weak solution of soap. The good effects of stopping -teeth, in the light of these experiments, are intelligihle. The penetration of acids and fungi is prevented. HaTIne WHEN S1ox.—lIt is the custom among acertain class of people, when a member of the family falls sick, to begin at once to ask, ‘Now what can yon eat?’’ Tvery one haa heard of the old atory of the man who always ate eighteen apple dumplinge wheu he was sick. On oue occasion when he was engaged upon the eighteenth, his little son said, ‘Pa, give me a piece,’’ “No, no, my son, replied the father, ‘go away; pais sick.’ When a young man has aurfeited in eeaeon and ont of season, nntil exhausted nature gives way, and a fever is coming on, the good mother ia iu trouble. She anxionsly inquirea, ‘Now, John, what can you eat? Yon must eat something! Poople can’t live withont food!” Then comes toast and tea, etc. The stomach is exhausted, and no more needs stimulating or food than a jaded horse needs the whip. What is needed is rest. Nine-tenthe of the acute diseases might be prevented by a few daye’ atarvation when the first indications appear, I dou’t mean complete abstinence in every case, but perhaps a piece of coarse hread, with cold water for drink. If auch a policy were generally adopted, whatruin would overtake the medical profession. How many physicians wonld lack for patients.— Hearth and Home. In the hydropathic treatment, drinking cold water immediately after rieiug, provided that breakfast be not taken for atleast half an hour, is prescrihed. The explanation given is that the internal donche acta upou the stomach as @ tonic, in thesame manner as cold applications externally, upon the skin, Action of Tobacco Smoke. According to Messrs, Yoh] and Bulemherg, the amount of nicotine in snuff and tohaeco for chewing is so miunte that nothing like nicotine-poisoniug can result from their use. The action of tohacco-smoke and tohaceo-jnice is uot due to nicotine, for it contains nove, hut to pyridine, picoline, collediue, aud other bases, forming a homologons series, which are produced during the comhnstion of the tohacco. The reason why strouger tohacco can ho smoked in a cigar than iu a pipe is, that in the pipe a large quantity of pyridino is formed, which ie vary volatile and stupefying; while ina cigar little pyridine and mueh colledine are formed. The nnpleasant symptoms expericnced hy persons just beginning to smoke, or who smoke to excess, as well as the.poisouous effect of tobaeco-juice, are not duo to nicotine, hut to the pyradiue and picoliue hases; aud they have probably heen attributed to nicotine because these bases, especially thoso having a high hoilingpoint, greatiy resemble nicotine both in smetl and in physiological action, producing coutraetion of the pupil, difficult respiration, convulsions and death. They do uot act so quickly when injeotcd under the skiu as when takeninto the stomach, and their action is less rapid than that of uicotine, Other plants which are sometimes used for smokiug, though they coutain no nicotiue, such as dandelion, willow wood and stramonium, yield pyridine hases, whose action are very like those from tobacco, though rather weaker, Pure picoline from Boghead coal had a similar action; and its vapor was poisonous, probucing irritation of the respiratory passages, shght convulsions, aud death. None of theso, except the bases from willow wood, produced contraction of the papil. The authors consider that the effects produced by opiumsmoking are not due to the alksloids iu the opium, hut to the bases formed dnring its combustion; and that tbe difference hetween it and tobacco is owing to different hascs heing formed hy their comhustion.—Arch. Pharm. and Chem. Color Blindness. The derivation of the designation of an affection of the eyes very commouly kuowu as Daltonism (color bliudness) is, as msny of our readers are doubtless aware, from the name of the great philosopher, the propounder of the atomic theory, who was attacked by it. Properly speaking it is simply iucapacity on the part of certain people to judge of color, or more accurately, of certain colors. Dr. Fayre has communicated to the Congress at Lyons the result of the researches, which, as chief physician of the Paris aud Lyons railway company, he has made on the subject, the object heiug to determine what influence this disease or affection may have on the general ssfety of travelers, According to this report, amoug 1196 different individuals examiued from 1864 to 1868, thirteeu cases of red-color blindness aud one of green were found. Again, among 728 subjects examiued between 1872 and 1873 he testifies to forty-two of color blinduess more or less developed. He further estimates the number of people in France sufferiug from this malady at nearly a million, and gives, as the most common causes of it, wounds, typhoid fever, syphilis, ete. The danger of such a disease existing, aud possible iu some instences without the knowledge of the subject or of his employers, is oue whieh deserves attention, for although we cannot point oureelves to any instances iu which errors have been made through it, neverthelese, Dr. Favre, as we understand him, is able to do s0, and we quite agree with him, wheu he saye thst the only effeetual preventive of the dangers which may possibly accrue fromsuch a malady isa periodical optical iuspectiou of all men who have to deal with colored signals, a mistake in the use of which might lead to such disastrous results. We recommend juquiry on this enbject to locomotive superintendents aud traffic mansgers.—The Enyineer. SuNsHINE anD SteeP.—Sleepless persons should court the sun. The very worst soporific ia laudanum, and the very best, sunshiue. Therefore it is very plain that poor sleepers should pass as wany hours aa possible iu the snnshiue, and as few aa possible in the shade. Many women are martyrs, and yet they donot knowit. They shut the sunshine out of their housea and their hearts, they wear yejls, they carry parasols, they do all poeeihle to keep off the most potent influence which is intended to give them strength and beauty, and cheerfulness. It is not time to change'all this, aud so get color aud roses in our pale cheeks, strength in onr weak backs, aud courage in onr timid eonls? The women of America are pale and delicate, but with the aid of eunlight they may be hloomiug and strong.— Home and Health, Borax ror Coups.—A writer in The Medical Record cites a number of cases in which horax has proved a most efleciive remedy in certain forms of colda. He statea that, in sudden hoarsenese or loss of voice in public speakers or singere, from colds, relief for an hour or s0, as by magic, may be often obtaiued by slowly dissolviug, and partially swallowing, a lump of horax, the aize of a garden pea, or about three or four grains, held in the mouth for ten minutea before apeaking or singing. This produces a profuse secretion of saliva,.or ‘‘watering”’ of the mouth aud throat, prohably restoriug the voice or tone to the dried vocal cords, just as wettiug brings hack the missing uotes to a flute when it is too dry.