Method of making Lmie cryJluUize, 53 



V. When mixed with fome drops of arfcnic acid, it dil- 

 folved completely, and reappeared with its iirft properties. 



After thcle trials 1 concluded that the acid of J5nignatelli 

 could be oiilv arfeniatc of cobalt dilfohed in cxccfs of acid. 



To afcerta'in this, I difloKcd pure oxide of cobalt in arfcnic 

 acid. I evaporated the folution to drvncfs, and added to the 

 refiduum diliilled water. After Itirring'the mixture, it was. 

 filtered. The liquid obtained had a light rofe colour, and 

 polfefled all the properties of the cobaltic acid. 



This liquor, mixed with alcohol, was abundantly precipi- 

 tated : this precipitate, when colleetcd, exhibited all the phcc- 

 noniena obferved in concrete cobaltic acid. 



It appears then certain, from the rcfults here given, that 

 no cobaltic acid exilts : that the combination of the arfcnic 

 acid and the oxide of cobalt led Brugnatclli info an error, 

 fince it is this combination with excefs of acid that i? ex- 

 tracted from zafler by the means defcribed in that memoir. 



XI, Method of meiVmg Lime cryJlaUize. By TaoMMS- 

 Dourr*. 



X HE cryftallizable quality of lime was firft difcovered by 

 Schanb. Rucholz obtained alfo very beautiful crvHals of this 

 earth by boiling it with its muriate. I have verified this dif- 

 covcrv, and have found that crv(hillized lime may be obtained 

 as well in winter as in funniier, only that the fait prepared 

 during the former feafon is in larger and longer cryftals. To 

 obtain thcfe crvftals, boil any quantitv, at pleafure, of muriate 

 of lime with a fourtli part, or lels, of cauliic lime, and con- 

 centrate it, if in winter, till a drop of the ley, made to fall 

 on a cold Hone, atlumes the confiftence of fyrup without 

 cryftallizing or becoming fixed. The matter is then to 

 be filtered throuizh a piece of clofe cloth extended above 

 an earthen or porcelain capfule, which mud be covered after 

 filtration bv a iiniilar capfule or a wooden lid, in order that 

 the matter mav cool as flowlv as pofli^Ie. In this manner 

 niav be obtainerl very long but very fine cryftals of lime, 

 which it is neceffarv to waOi in alcohol in order to free 

 them from the adhering muriate. This operation cannot be 

 undertaken with lei's tlian fonit pounds of the muriate of 

 litne. It is well known that, \\ hen jnuriate of amnionia is 

 diflillcd with excels of lime to decompofition, a part of the 

 refiduum adheres fo ftronalv to the vefl'el that it is ainioft 



• Fiom Jouiiutt dc Chimi' . bv J. B. Van AIoiis, No i. 



D 3 iirpiiflible 



