406 Miscelianeous Intelligence. 



water, requiring only about 300 times its weight tor that pur- 

 pose. On cooling, the calculous matter did not immediately 

 separate, but after some days a great part of it was deposited. 

 When chemically examined it was evidently urate of ammo- 

 nia. 



Dr. Prout also possesses a fragment of another small cal- 

 culus, having precisely the same colour and properties with that 

 described. It was taken from a boy under the age of puberty, 

 and was accompanied, as was also the first, by great irritation. 



The characteristic properties of this species of calculus ap- 

 pear to be the following : 1 . Their colour and general appear- 

 ance, which are peculiar, 2. Their solubility in water. 3. Their 

 yielding ammonia, when treated with fixed caustic alkali. To 

 which, perhaps, may be added, 4. Their property of decrepitat- 

 ing before the blow-pipe. — Medico-Chirurgical Transactions, x. 

 p. 389. 



11. Properties o/Lithia. — Dr. Gmelin, of Tubingen, has been 

 engaged in experiments on lithia and petalite. He obtained 

 pure lithia by adding barytcs- water very carefully to sul- 

 phate of lithia, until nothing remained in solution but the caustic 

 alkali. The solution was rapidly filtered into a tubulated retort, 

 and evaporated in a sand-bath. When the liquid in the retort 

 became concentrated, a white powder separated, and likewise 

 some small granular crystals. These fell wliile the liquid was 

 still hot. The retort, still closed, was then placed in a cellar. 

 Neither the powder nor crystals appeared to increase on cool- 

 ing, and hence it is considered that lithia is not much more so- 

 luble in hot, than in cold, water. The concentrated solution 

 being then evaporated in a platinum crucible by a spirit-lamp, 

 dry caustic lithia was obtained, in which acids could detect no 

 trace of carbonic acid. 



When heated in a platinum crucible it melted before it be- 

 came red hot. The fused mass was transparent, but on cooling 

 in the open air became opaque, from the absorption of carbonic 

 acid. Caustic lithia has a sharp burning taste. It destroys 

 the cuticle of the tongue, and appears to equal potash in 



