GLYCINE. 



fi'.fpfnded and e:<pofed by an sstcnl of furfiicc to the action 

 of tlic alkali. If the treatment dofcribcd is pioperlv con- 

 d'ltteu, the fiifed mafs, wlicn lofteiied with water, will be 

 entirely diiTolved by muriatic acid, afiittcd by a llijrht digell- 

 i"ng heat : the muriatic iolution thus procured mull be eva- 

 porated to drynefs. A hrge quantity of water will difTolve 

 the foliible falts, and leave the principal part of tlie illex, 

 which is to be fejiarated and well wafhed on a filter. The fil- 

 tered foluticn is to be precipitated by carbonat of potafti. 

 The precipitate, confiftiiii; principally of alumine and theearth 

 in queftion, is to be difTolved in dilute fulphuric acid, and 

 evaporated to the proper confidence to afford cry (lals of alinn. 

 If the precipitate produced by carbonat of potafli has been 

 •well walhed, it is nt'cefiary to add a little potadi to tlie ful- 

 phuric folution. When the foKition, on a fecond or third 

 evaporation, and addition of potalh, ceafes to yield any 

 more cryftals of alum, the mother liquor is to be mixed with 

 a folution of carbonat of ammonia, greatly exceeding the 

 quantity necelfary to faturate the acid, and to be transferred 

 to d bottle having a ground Hopple : the mixture is to be 

 well agitated, and carbonat of ammonia is to be added till 

 the precipitate which firit appeared is re-diflolved, or no 

 longer diminifhcd by frcfh portions of the carbonated alkali. 

 The fo!ution of the triple compound of glycine carbonic 

 acid and ammonia is to be filtered in order to feparate the 

 fniall remaining quantity of alumine, and then boiled till the 

 vapour ceafes to change the colour of turmeric paper, or till 

 it no longer has an ammoniacal fniell ; when all the carbonat 

 of ammonia being driven off, the whole of the glycine will 

 be found precipitated in the form of a white granular pow- 

 der coi.bined with carbonic acid. This powder is to be 

 wafhed in a filter, till the water ceafes to afford a precipitate 

 with muriat of barytes and lime -water ; it is then to be 

 dried, and heated to rednefs : by this means, the water and 

 carbonic acid, amounting to about half the weight of the 

 whole, will be expelled, and the glycine, if it does not 

 effcrvefce v\'ith acids, will be left in a perfectly pure ilate. 



G-vcine thus procured, is a fnow-white powder, foft 

 and fo;.ievv!iat uncluous between the fingers, ver\- adheiive 

 to the tongue, and dellitute both of fmell and taffe. Its 

 fpecific gravity is 2.976. It produces no change in the co- 

 lour of vegetable blues. Neither oxygen nor nitrogen has 

 any aiticn on it, nor does it fuffcr any change by cxpofure 

 to the atmofphere ; as carbonic acid and moiitnre do not ap- 

 pear to beabforbedby it. It forms, with a fmall quantity 

 of water, a (lightly duclile pafte, that po'feffes much lefs te- 

 nacity than that of aluiy.ine. Glycine has not yet been fufod ; 

 ft neither contracts nor hardens Avlien heated, nor is it altered 

 by cxpofure to the mo ft intenfe fire. With borax it forms 

 a' white tranfpareut glafs, which does not become opaque on 

 cooling. It refufes to combine dircClly with f-.iipliur or 

 phofphorus, but it appears from Fourcroy that a lulphurct 

 may be formed by decompofing the fulphat of glydnc by 

 cjiarcoal. Glycine is foluble in a faturated folution of f«l- 

 phuretted hydrogen. A hydro-fulphuret of this earth, it is 

 likewife faid, may be obtained by difiblving the fulphurct in 

 water. In thefe properties it approaches the alkaline earths, 

 and conllitutes apparently the link of union between them 

 and the clafs to which it belongs. It is diffolvcd by both the 

 fixed alkalies in their liquid Hate, but in a lefs degree than 

 alumine, and, like aluniine, it is not taken up by ammonia. It 

 is diffolved in a folution of carbonat of ammooia, as has al- 

 ready been mei.tioned. It very readily unites with acids. 

 All its foluble falts produce, when firll tilled, the fcnfation 

 of fweetncfs, which gradually becomes aftringer.t. 



In relation to its affinity for acids, glycine appears to be 

 fctermediatc between alisiDine and magnelia, for it decom- 



pofes only the falts of alumine, yttria, and zircon. And the 

 Older of its affinities ismuch the fame, according to Fourcroy, 

 as that of the other earths, fulphuric acid holding the «rft 

 place, and nitric, muriatic, phofphoric, fluoric, boracic, and car- 

 bonic following. No experiments have been undertaken 

 yet, to afcertain what combinations glycine is capable of form- 

 ing with the earths and metall-e oxyds. 



Yttria and alumine are the only earths for which gly. 

 cine is liable to be miftaken : the properties in which it re- 

 fembles them are, rather unfortunately, of a mod linking 

 kind, but it has a number of other characters which are very 

 diltinft, and fully demonilrativc of its peculiar nature. Gly- 

 cir.e is fimilar to alumine, in being foluble in caullic folutiolis 

 of the fixed alkalies, and in fome of its phyfical qualities; 

 but it differs from alumine in affording with acids fweet alirin- 

 gent falts ; in not yielding alum with fulphuric acid and pot- 

 alh ; in pofrefllng a greater affinity for acids ; in being en- 

 tirely foluble in carbonat of ammonia; and laltlv, in not beifig 

 precipitated from its folutions by oxalat, tartrat, or pruffiat 

 of potafh. It is to be diftingaithed from yttria, bv its 

 greater folubility in carbonat of ammonia, the latter requir- 

 ing for its folution five times as much carbonated alkali as 

 gl) cine, by its fait.'; occafioning a precipitate, when added 

 to any of the fuccinats, by the infolubility of yttria in 

 fixed alkaline folutions, and by the precipitate which the 

 falts of yttria afford witli pruffiat of pot-afh. 



Glycine was confidered as a fimple body till the import- 

 ant difcoveries of Mr. Davy gave rife to new analogies ; and 

 though the compound nature of tliis earth is not yet fully 

 demonrtrated, yet there is every reafon to believe that gly- 

 cine, like the alkalies and alkaline earths, is a cictallic oxyd : 

 and the refults of the experiments which Mr. Davy made on 

 this body are explained belt on fuch a fuppofiti'on. This 

 gentleman negatively electrified glycine, fiightly moiftcnid 

 in contact witli an amalgam of potallium, under naphtha, by 

 a battery of 500 plates. After an hour the amalgam was 

 thrown into water, and an alkaline folution was produced, 

 which became cloudy when neutralized by acid, thus indi- 

 cating the prefence of the earth. Mr. Davy, following the 

 nomenclature which he has adopted in refpcdt to the new- 

 metals, has propofed glucium for the name of the metal 

 of glycine, when its exigence is no longer do-jbtful. 



Carbonat of glycine, as well as all the other falts of this 

 earth, has not yet been difcovercd ready formed in nature. 

 It is procured by precipitating the fulphat, nitrat, or moriat 

 of glycine, by either of the carbonated fixed alkalies. The 

 preci[)itate, which is the fait fought after, being well waftied 

 and dried, appe.irs in the form of foft white powder, having 

 a grcafy feel and great light ncfs. Carbonat of glycine is 

 iuloluble in water, and it is unaltered by expofure to the air. 

 It is deconipoled by p.ll the acids; and by the action of a 

 red heat : moll probably all the alkaline earths deprive it of 

 carbonic acid in the moift way. According to Klaproth it 

 is compofcd of 



Glycine - - - 53- 

 Carbonic acid and water - 47 



ICO 



PLofphat of Gljchu. — Phofphat of foda, added to a neu- 

 tral folution of nitrat of glycine, throws down this fait 

 either in a white pulverulent form, or in a mucilaginous 

 fiate. It is infoluble in water, infiptd and uncr)-llallizable. 



It is not decompofed by a violent heat, but it fufcs into 

 a wlilte tranfparent glafs, that docs net become opaque on 

 coohng. Phofphat of glycine is foluble in phofphoric 

 acid. The fulphuric and nitric acids firft diffoU-e this fait, 



and. 



