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of (lie co;iibufl.ion of alooliol, Lavoificr proeecdid la re- 

 jM-at tlie experiment, in veiltls which niiglit cktcrmine the 

 rrfiilt wit'.i accuracy. He employed, for this purpole, a 

 brge bell glafs, holdnij; from 700 to 800 cubic inches, and 

 inverted over a mercurial trouijh. A fmall hurp filled 

 witli a known weight of alcohol, was introduced under 

 the glafs fwimming on the furlace of the mercuiy, and 

 the wick was armed with a vciy minute portion ol pliof- 

 phonis. The atmofpherical air within the glafs was 

 lucked out by a fyphon, till the mercury rofe to a certain 

 height which was nottd ; and tlie pliofphorus on the wick 

 being then kindled by a hot iron, the fpivit fooj) took 

 iire. As the air withiii the glafs would be foon cohUniK-d, 

 and the inflammation of the fpirit Hopped, a conllant 

 fupply of oxygen gas was fent into the glafs through a 

 fyphon tube, connected with a refervoir of this gas, and 

 which palled under the mercury into the glafs where the 

 combuiiion was going on. Great precaution was required 

 not to let in more oxygen than was barely necefTary to 

 keep up the combuiiion ; otherwiie the heat, volatiliz- 

 ing pait of the fpirit, would have filled the glafs with 

 v.ipour of alcohol, and this mixing with the oxygen, 

 would have fuddenly exploded by the combuflion. In 

 this, as in other refpecls, the combuftion of alcohol 

 ilrikingly refcmbles that of pure hydrogen gas. The ex- 

 perinient was at laft flopped by the quantity of carbonic 

 acid generated ; and on examining tlie rekilts, (proper cor- 

 reclions lieir.g made for prelTure and temperature) it was 

 found, that 93.5 grains of alcohol and 110.32 grains of 

 oxygen had been confumed. The produiEls of thefe were 

 93. S grains of carbonic acid and lo6.2 grains of water, 

 which iail therefore exceeded by 12.7 graias the quantity 

 of alcohol employed. From thofe data^ and from previous 

 experiments (wherein Lavoifier eftimatcd, that 100 grains 

 of oxygen take up 38.88 grains of carbon, for the pro- 

 duction of carbonic acid gas ; and that the fame quantity 

 of oxygen takes up 17.64 grains of hydrogen for the pro- 

 ■dudion of water), he concluded the compofition of alcohol 

 to be the following, 



Carbon - - . . -28. 53 



Hydrogen - - . . -7. 87 



^Vater already exiiling in the alcohol 6 3. 6 



We may obferve, however, that the refult of this experiment 

 can only be confidered as an approximation towards the 

 truth, fmce the ellunation of the component parts of alcohol 

 here given, does not agree with that w'hich is deduced by 

 the fame chemill, from the refult of vinous fermentation. 

 Neither is there any light thrown on the mode of union 

 between the compoient parts, and their degree of oxygen- 

 ation as they exill in the fpirit before combuIl;i<ni. 



Alcohol has likcwife been more dircclly decompofed 

 witliout the accelFion of oxygen gas. Dr. PrielUey pro- 

 cured iuriammable air by paffmg the cleitric fpark through 

 fpirit of wine. But the moll ilriking experiments on this 

 fubjeft, performed by this excellent philofopher, were the 

 dccompofition of fpirit by paffing it through red-hot 

 tubes, both of earth and raetal. He lirft tranfmitted two 

 ounce meafures of alcohol, reduced to vapour by boiling, 

 through an ignited porcelain tube, and procured 1900 

 ounce meafures of air, " which was all inflammable without 

 " any mixture of fixed air in it, and which burned with 

 " a blue lambent ilame." (\Ve here quote the veiy words 

 of the author, which the writer of the article Alcooi., in 

 the Encyclopedic Methodique, has made to correfpond with 

 the experiments of Lavoificr, by adopting the following 



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fingular tranflatlon — M. Priejiley, en faifant pajfer de P ako»I 

 dans un lube d'argile rotigi au feu, en a retire du gas hydro- 

 gene mile de ga% acide carloiiique.) Dr. Prieflley's next 

 experiments are ftill more curious, as they determine the 

 cxiflence of carbonaceous matter in fpirit of wine. Hav- 

 ing found iiUereiling refults from the tranlmifTion of the 

 vapour of water through a heated copper tube, he repeated 

 the experiments, only fubflituting the vapour of fpirit of 

 wine for that of water. " In this cafe," he obferves, 

 " the vapour of the fpirit had no fooner entered the hot 

 " copper tube, than I was pcrfedly allonifhed at the rapid 

 " production af air. It refembled the blowing of btl,- 

 " lo\.s. But I had not ufed four ounces of the fpirit of 

 " wine before I veiy unexpedledly found that the tube 

 " was perforated in feveral places, and prefently afterwards 

 " it was fo far deilroyed, that in attempting to remove 

 " it from the fire, it adlually fell in pieces. The infide 

 " was full of a black footy matter, refemhling lamp-hlack?* 

 He then varied the experiment by ufing earthen tubes, 

 placing within them copper filings, and tranfmitting the 

 vapour of alcohol. The copper was as before, converted 

 into a black friable fubflance, obvioufly produced by the ■ 

 addition of carbonaceous matter furnifhed by one part of 

 the fpirit, whilll the other part appeared in the form of a 

 copious llream of inflammable air. It is however by no 

 means the whole of the charcoal of the alcohol which i» 

 detained by the copper, for much of it efcapes mixed with 

 the inflammable air in the form of fine foot, giving the 

 gas the appearance of a denfe black cloud ; and when 

 the tube is llrongly heated, this volatilized charcoal will 

 give an uniform black coating to any balloon or large veflel 

 in which the gas is received. Dr. Pricltley found fomc 

 other metals to undergo a fmiilar change by the vapour of 

 alcohol, but none in fo Ilriking a manner as copper. On 

 heating fome of this charcoal of copper, as he calls it, in 

 oxygen gas, he found it to burn very readily to a certain 

 point, after which the remainder could not be again 

 kindled. The gas produced by the combuflion, was pure 

 fixed air or carbonic acid. 



The excellent Dutch chemifts, of the Teylcrian inflitu- 

 tion, Van Maritm and colleagues, repeated Dr. Prieftley's 

 experiments with great accuracy, and found the fame refults 

 in every effential particular. They employed, as well as 

 Dr. Prieflley, Wedgwood's porcelain tubes, which they in- 

 clofed in iron tubes to prevent the fudden aftion of the fire 

 which is apt to crack them. One extremity of the earthen 

 tube received a fmall retort in which was put the alcohol, 

 and the other entered a metallic Icrpentine tube, immerfed 

 in a refrigeratory, and provided at the further end with a 

 bottle to receive the gafeous produfts. In the firfl experi- 

 ment which was performed, an ounce and a half of alcohol 

 in vapour had been tranfmitted through the heated copper, 

 and had produced about fix cubic feet of inflammable 

 air. 



In the fecond experiment the heat was greater, and the 

 produftion of the gas more rapid. In all, the copper was 

 reduced to a black and very friable fubflance, which fell to 

 pieces between the fingers. The proportion of charcoal 

 added to the copper by the experiments, varied at diftcrent 

 times apparently owing to the greater or lefs rapidity with 

 which the proeefs was conducled. Dr. Prieflley had united 

 446 grains of charcoal to 28 of copper, in one inflance ; 

 and J08 to 19, in another: but the Dutch chemifls found 

 a much lefs proportion of charcoal, being only an addition 

 cf 292 graiiiii to 748 of Copper in one cafe, and in another, 

 iSo oi charcoal to 612 of the metal. Tlie great difTerence 

 in the refults is, however, of little confequeace in attempl- 

 1 ing 



