SPIRITS. 



•vhich is all that mufl be ufed in this dillillation ; and the 

 fait having been firft decrepitated, never makes any change 

 in the alcohol by adding any thing to it. By this means 

 an alcohol is prepared perfeftly pure, and fit for all the ufes 

 of chemiftry. 



For the tells and properties of pure alcohol, fee Al- 

 cohol. 



M. Reaumur difcovered, that a mixture of fpirit of wine 

 and water acquired a fpecific gravity greater than that which 

 would arithmetically refult from the proportions employed 

 of each of thcfe liquors. Thus, fifty meafares of fpirit of 

 wine, and fifty meafures of water, mixed together, were 

 found to make only ninety-eight meafures ; but in what pro- 

 greflion the deiifity is increafed by mixing various propor- 

 tions of the two liquors, had not been determined till M. 

 Briflbn made a fet of experiments with that vie>v ; an ac- 

 count of which is given in the Memoirs of the Academy of 

 Sciences of Paris, for tlie year 1769. 



From his experiments he has conllrufted the following 

 table, which (hews tliis progreffion, and alfo enables us to 

 difcover the proportion of fpirit of wine and water, in any 

 given mixture of thele (as brandies, rums, &c. ), the fpecific 

 gravity of which is found to correfpond with any of the 

 fpecific gravities in the table. Thus, for inftance, if we find 

 upon accurate trial, that the fpecific gravity of the rum, 

 brandy, or other mixture, whofe ftrength is required to be 

 known, be to that of water as 9427; to looo, we learn, by 

 infpeftion of the table, that this fpirituous mixture confifts 

 of equal parts of water and fpirit of wine, of which fpirit 

 the Itrength is fuch, that its denfity is to that of the water 

 as 837 to 1000. The firft column (hews the proportion of 

 well redificd fpirit of wine in the mixture ; the fecond co- 

 lumn fhevvs the proportion of the water in the mixture ; the 

 third column fhews the fpecific gravity of the mixture ; the 

 fourth column (hews the difference between the fpecific gra- 

 vity of the mixture and that of the preceding mixture ; and 

 the fifth column (hews the proportion which the feveral aug- 

 mentations of denfity, caufed by penetration of the two 

 liquors, have to each other, that is their progreflion. 



Spirit of wine is ufed in dyeing, as a non-colouring drug, 

 »nd though it gives no colour itielf, it ferves to prepare the 

 fluffs to receive other colours. Its confumptiou is alfo very 



confiderable in feveral other works and manufaiaures, parti- 

 cularly the making of varni(h. 



Proof-fpirit cannot be ufed for burning in lamps, for dif- 

 folving refins, and for making varniiTi ; and there is alfo a 

 great number of tinftures, folutions, and mixtures, for which 

 it cannot ferve ; but retftified fpirit, or alcohol, beCdes its 

 ready ufe for medicinal purpofes, may, when the fpirit is of a 

 proper kind, be made into punch, and all other mixtures, 

 with greater purity, and much greater certamty and exad- 

 nefs in point of ftrength. See next article and Ar.coiioL. 



Spirits, in the Materia Medica, " retftified fpirit" of 

 the London Pharmacopeia ; " alcohol," " fpiritus vinofus 

 reftificatus five puriflimus," Ediiib. ; " fpiritus vinofus 

 reftificatus," Dub.; is alcohol nearly in the higheft ftate of 

 concentration in which it can be eafily prepared m the large 

 way for the purpofes of trade. The I^ondon and Edin- 

 burgh colleges ftate its fpecific gravity to be to that of water 

 as 835 to loco, while the Dublin college ftates it at 840. 

 The Edinburgh college names this fpirit alcohol ; but direc- 

 tions being given both by the London and Dubhn colleges, 

 for the preparation of a ftill ftronger fpirit, the name of 

 alcohol, in their pharmacopeias, is judicioufly retained for the 

 ftronger fpirit, while that of reftified fpirit is applied to the 

 prefeut preparation. 



The alcohol of the Lond. Ph. is prepared by taking of 

 reftified fpirit a gallon, and of fubcarbonate of potafs, 

 three pounds : add a pound of the fubcarbonate, previoufly 

 heated to 300 degrees, to the fpirit, and macerate for 24 

 hours, frequently ftiaking the mixture ; then pour off the 

 fpirit, and add the remainder of the fubcarbonate, heated to 

 the fame degree ; and laftly, diftil the alcohol from a water- 

 bath, and preferve it in a well-clofed veflel. Tlie fpecific 

 gravity of this alcohol is to that of diftilled water as .3 15 to 

 1,000. 



The alcohol of the Dub. Ph. is prepared by taking of 

 reftified fpirit of wine, a gallon ; pearl-afties, dried at a heat 

 of 300°, and ftill hot, a pound ; cauftic kali, in powder, an 

 ounce ; muriate of lime, dried, half a pound. Mix the 

 fpirit and the kali ; add the pearl-alhes, previoufly reduced 

 to powder, and digeft the mixture for three days in a clofed 

 veflel, frequently (haking it ; then pour off" the fpirit ; mix 

 with it the muriate of lime ; and laftlv, dillil with a moderate 

 heat, until the refidue begins to thicken. The fpecific gra- 

 vity of this fpirit is to that of diftilled water as 315 to looo. 



Reftified fpirit of the fpecific gravity of 835, contains 

 about 15 per cent, of water ; and to free it from this is the 

 intention of the above proceffes. The Edinburgh college 

 has no procefs for the preparation of pure alcohol, which 

 may be eafily difpenfed with ; but it has very improperly 

 given this title to the reftified fpirit of the other pharma- 

 copeias. The theory of the operation is fufficiently obvious. 

 The affinity of the alkali and the muriate of lime for water 

 is much greater than that of the fpirit : it is, therefore, at- 

 trafted by thefe fubftances, and prevented from rifiug with 

 the fpirit during the dillillation, by which mean* the alcohol 

 comes over in a very highly concentrated Hate. Of the two 

 procefl'es, that of the Dublin college is to be preferred; 

 muriate of lime being a much more powerful agent for fcpa- 

 rating the water, which is the objeft in both, than fubcar- 

 bonate of potafs. 



Dr. Black thus obtained alcohol of the fp. gr. of 800°, 

 and Richtcr procured it fo low as 0.792, in the temperature 

 of 68° Fahr. at which degree of concentration it may be 

 regarded almoft as pure aleolK)l, or alcohol perfeftly free 

 from water. That of the pharmacopeias is not free from 

 water, though more than fuflicientiy concentrated for all the 

 purpofes of pharmacy. 



4 C a The 



