1820.] composed of the Lit/iate of Ammo/lid. 437 



nearly to the wood-hrown of Werner.*) The difterent layers, 

 however, differed somewhat in intensity, which caused the lami- 

 nated structure to be visible to the eye. Between some of the 

 layers also there were minute depositions of the earthy phos- 

 phates, which render this structure still more sensible. The 

 nucleus exhibited the same general appearance as the rest of the 

 calculus, except that it appeared to be made up of a fine powder 

 and a few larger grains, loosely agglutinated together. 



It was sparingly soluble in cold water, 'j- but it dissolved readily 

 in boiling water (especially when in a state of fine powder), 

 requiring only about 300 times its weight for that purpose. Oa 

 cooling, the calculous matter did not immediately separate, but 

 after some days a great part of it was deposited. 



It readily dissolved in solutions of the fixed alkahes, and at the 

 same time a strong smell of ammonia was exhaled. When 

 muriatic acid was added to this solution, lithic acid was preci- 

 pitated. 



In nitric acid it dissolved readily, especially with the assist- 

 ance of heat, exhibiting the same phenomena as lithic acid whea 

 similarly treated. 



Muriatic acid, in which it had been digested, was found to be 

 converted into muriate of ammonia. 



Exposed to the action of heat by means of the blow-pipe, it 

 decrepitated so strongly that it vvas difficult to ascertain the 

 effects produced by this agent. When reduced to powder, and 

 exposed to heat, it first appeared to give off ammonia, and after- 

 wards to burn with the same phenomena as lithic acid. It lefta 

 minute residuum, which strongly reddened turmeric paper, and 

 appeared to consist partly of lime (and alkali), and partly of the 

 earthy phosphates. 



From these properties it is evident that this calculus consisted 

 principally of tlie lithate of ammonia, i 



* Sfe Werner's Noiiiciicladire of Culoiirs, 1>3' Patrick Svme. 

 + One part of the excrements of the boa constrictor (wliicii is lilh.'ilc ofammo- 

 nia) at 60° rc(;uired about 480 parts of h ater to djssolve it. 



At 90= 300 



At 212" 240 



■Rut til- calrr.liis above de.-cribed uas foiii'd to be M):iiewliat less soluble tlian (Itis 

 >nbs:;iM!e, [irobably on account of its compact •.l;ile of ;j!;;;re;;alion. 



X 'Ibc f(illo\\in;C is I'oiiicroj's dcscripliiiii of lliis species of calculus, wliich 

 <loes not difier nincli from the above. " Les calculs d'lirale d'liinmoni.ique, bieii 

 tliaractcri.sC-s par leiir dissohibilitc dans les le."ive^ d'aUalis fixes cau-ti(ptes, mais 

 avec uii de^.ii^empiit abondant d'anitooniaqne, sont ordinairen-.ent pclils, d'une 

 coiilcur pule (Ic cafe an lait, on d'uii j;''^ lirantsu. celle nuance, fi.rmci de coiiclie^ 

 fine- qu'on dctache facilcnient lis nr.e,-. dc- autie/, rt c[ui sont li-ses par les surfaces 

 <jni selouchenl ; presipic toiijours conteniinl un iio\an I'.ont on ^t-paleai^(nlcnl I'cu- 

 vtlwppe. I.eiir forme la pins ordinaire, est split I'oidale, alonjrcc, coniprioiee, quct- 

 ijuefois amypidaloide ; leur surface est orilinaircuient lis-e, jamais tuberciileiise, 

 qiclipiefois brillanle el ci\slalline ; leur pe^anll nr spec ifique \a de l.y-iS a l.'JSO, 

 I'tau seulc les dissnul, sirtont cpiand elleest ch:iu(lc, ct qiiand ils soul divi-r- clcu 

 IMius-itre line. I.cj acidi's, le muriatiipie surmul, leurenltvenl rammi.iiiaquc, « 

 luiMciit ;ful I'acide urique,qui sc dissunt rn-uilc dans la polassc tans cllVrvcsceuce: 



