132 PHARMACBUTICAL PREPAR ATTOt^S. 



feaiy at reft in the phial, which was half full, and clofely 

 Thefe cryflals flopped. After this period I found the furface of the fluid 

 "\U'^Y-^'^ covered wifh a faline cruft, from which tliot downward prif- 



in thin ftiinjng ' • i i j v l j 



lamina:. malic cryftals in fliining laminae, an inch long, and a line broad, 



diverging from a centre. I will not defcribe their geometrical 

 ftrudurc, for they are extremely thin, and embedded in a fluid 

 too vifcous for me to take them out without breaking, Befides, 

 they are flill increafing; laminae rife from the bottom of the 

 veflel, which touch the furface of the glafs, and feem pre- 

 paring to intermix with the ramifications that ftioot down from 

 tiie upper ftratum. The fides of the veffel are the feat of this 

 beautiful cry flail iz;ation. The centre remains in part concrete 

 or fluid, whence it follows, that if a very regular diflipation 

 of the particles of the liquid acid of phofphorus be occafioned 

 by repofc, the fides of the veflel contribute to it in great mea- 

 fure by affording fixed points, to which the pofitions of affinitj 

 nioft favourable tocryftallization dired themfelves. 



Puriti/ of Phofphorus, 

 Charcoal com- Prouft has informed the public, that, in the diftillation of 

 bines with phof. phofphorus, a combination of this fubftance with the charcoal 

 \hllm!Iihn. conftantly took place. This important difcovery extends much 



farther than its celebrated author has fliewn. 

 Phofphorus pu- Take the moft brilliant and moft tranfparent phofphorus* 

 It^^'^.'A which has not only been ftrained through chamois leather, ac- 



method. cording to Woulfe's method, but has alfo been diflblved feveral 



Muffin. Pufch- times in nitro-muriatic acid, as done by Count MuflTin-Pufclikin, 

 ^"''» c! which has been treated with oxigenated muriatic acid, after 



or lucVs, ^^^ "^°^^ ^^ ^^'■- J"^^ °^ Wurkburg ; let it be heated gently 

 ffill flicwsmarks in along flender tube; red parts will feparate from it. Put a 

 ''^"^* few grains of this phofph .rus, which is conceived to be fo 



pure, on a fil.er fpoon, and fet fire to it; a red trace will re- 

 main. If the fpoon be heated in the dark, the red trace will 

 be feen ftill to burn, and a coal will remain impregnated with 

 phofphoric acid. 

 HcaMnewUh Mr. Jucli has aflerled, that his phofphorus is extremely 



eauftic alkaji pyrg becaufe it no longer becomes black when heated with 



inc rablc of*' /., r.i/-. r 



proving the pu- cauftic alkali; but it is in faft becaufe the pholphure of car- 

 rity of phofpho- jj^^g jj unalterable by cauftic potalh. According to the indifput- 

 able authority of Prouft, this re-agent is incapable of proving 

 Heated oxige- the purity of phofphorus. I confefs, that heated oxigenated 

 nated muriatic muriatic 



