180.5.] 



Formation of Muriatic Acid by Galvanif/n, 



scg^ 



.*ith oxygen ; and laflly, others as a 

 fimple (ubitance naturally acid. But 

 thel's o;>inions have not contributed to the 

 advaiicenitnt of fctence, and are ju3ly 

 (Cfteemed as mere hypothefes> deftitute of 

 proof 



" Having, however, negleJ^ed thefe 

 hypoilieles, and confuiered the means hy 

 which the Hifcovery of the nature of this 

 acid has been hitherto attcni;>ted, it ap- 

 peared tr> nne that one had not yet been 

 tried, viz the con'inued a£tion of the pile 

 of the celebrated Volta ; and I fufpefted 

 that it might '.(hfi in leading me to difco- 

 verles which had hitherto eCciped the re- 

 fearcli--f experimtBtai philofophers. As 

 far as I can judge, my endeavours have 

 been crowned »iih (uccefs, and have fur- 

 rilhed me with fatisfaiTory evidence of 

 the nature cf the conftituent principles of 

 muiiatic acid. 



" The fimplicity of the apparatus, and 

 of the means adopted to atiaiii my views, 

 the care with which I have endeavoured to 

 avoid every fource of error, have I hope 

 fufficiently fecured me againft thofe illu- 

 fions which fi. queiitly deceive young m-rn 

 ardent in the purfuit of fcience, and even 

 thofe pra£tifed in the art of extorting 

 from nature hrr fecrefs. Want of time 

 prevents me from relating the feries of 

 experiments by which I arrived at the 

 difcoveiy I have mentioned ; but you may 

 fee it by perufing the manufcript of my 

 memoir, which will be immediately pub- 

 liOied, to fubmit my lefearclies and their 

 refulrs to 'he jud 'men' of th^ learned.— 

 For the prefent I (ha 1 feled from the tx- 

 periments and fails therein defcribed thofe 

 whi.'ih are dccifive, and which eftibli(h in 

 an evident tninrtr the following truths : 



*' I. Muriatic acid is an oxide of hy- 

 drooen, and consequently compofed of 

 hydrogen ind oxygen. 



" II. In the oxygenated muriatic acid, 

 and therefore a fortiori in muriatic acid, 

 there is a much lefs proportion of oxygen 

 than in water. 



** III. Hydrogen is fufceptible of very 

 many and different degrees of oxidation, 

 contrary towiiat is univrrfaily believed by 

 pneu.naiic chemu'ts, who aflert that hy- 

 drogen is fufceptible only of one invariable 

 degree of oxidation, that in which it form* 

 wa-er. 



" Having at firft examined the pheno- 

 menon of the decoinpofition of water by 

 the Qalvanic piie, ard having by accurate 

 expcrimrn'safceriained ihe ime theory, I 

 readily difcovcred a very fimple and exadt 

 apparatus, in which I could diltinily per- 

 ceive Uie changci whicli happen to wattr, 



which, from the continued aflion of th^ 

 Galvanic pile, is continually lofing its ox- 

 ygen at the furface of a wire of very pure 

 gold immerfed in it. 



" I therefore proceeded to examine 

 thefe gradual ch:inges of wa:erthui lofing 

 its oxygen, and I at laft obfervel a very 

 lingular fa£l, which unequivocally indi- 

 cated the formation of an acid. In other 

 antecedent experiments I had examined 

 the nature of the air obtained before ar- 

 riving at this remarkable point, and I al- 

 ways found, by means of the eudiome'tr 

 of Giobert, that it was very pur« oxygen, 

 as the refiduum fcaicely amounted to one- 

 fixtieth. 



" Having thus examined the nature of 

 the air formed in vai iousexpei iments from 

 the firft moment of decompolition until 

 there were evident indications of (he for- ' 

 mation of an acid, I began to endeavour 

 to determl.ie in a more pofitive manner 

 the exiftence and naruce of this arid. 



" When the water, or, to foeak more 

 accurately, the refidual fluid, occupied 

 about half the capacity of the receiver 

 which at firft contained the waiter, this re- 

 fidual fluid piefe'ited the following charac- 

 ters : 



" Its col-iur was an orange-yellow, 

 more or lefs deep according as the bulk of 

 therefid'ial liquor was greater or lefs, and 

 it reiembled in appearance a true folution 

 of gold. 



" From the inferior orifice of the vefTel, 

 which was clofed with a piece of taffety, 

 and then with d'.-uble bladder, there 

 efcaped a fmelj which was eafily recog- 

 niftd to be that of oxyge.'.ated muriatic 

 aci I. 



" The gold wire had in part loft its 

 metallic lulfre, aid i.s furface appeared as 

 if corroded by a lolvenf. 



" The bit of tafFcty which had been in 

 contaft wiih the coloured fluid, in con!"e- / 

 quence of its a'^lioii, waseafily tcrii, as is 

 ufud with fiinil ir bodies when half burnt 

 (femi-combujlo) . 



" Around the edges of the VefTel, on 

 the bladder, liiere wt* formed a deep 

 purple ring, wliich furrounded a rir.ular 

 I'pace rendered entiieiy c lourle.s o. wh'te, 



<« A drop of iii.s fluid tmgei' th^ (kin 

 of tne hand, at'er (bme hour.s, wih a 

 beauiful r'dc-colour. 



" Having oiitiined in various fuccefTive 

 experi'Tients the fame liquid, po.Tifli ig 

 cooltamly the fame provcnies, I chofe 

 that obt lined in :h(. lalt cxpeiiment to 

 lubjcCt ii to chemxal exaiiiioaiion. The 

 very able chemiit ot 'h.s iinivt'''(i'-y, S'g, 

 Giiifeppe Branchi, had the gooJncfs to 



enter 



