152 Scientific Notices — Chemistry. [Aug. 



the nitric acid, and the sulphur is disengaged in a solid form. If 

 the flask be closed with the finger, so that the gas which becomes 

 heated cannot escape, its temperature is raised so much as to 

 produce combustion with a beautiful flame, and a slight deto- 

 nation, which forces the finger from the mouth of the flask. 

 This experiment may be made without the least danger, with a 

 flask containing four or five cubical inches of gas. Berzelius. — 

 (Journal of Science.) 



9. Urinary Calculus. 



M. Laugier has lately examined a calculus taken from a young 

 man of 22 years of age. Although this calculus is formed of 

 substances which are frequently met with in this sort of concre- 

 tions, yet its peculiar appearance, friability, and the proportions 

 of the elements which it contains, induced M. Laugier to publish 

 an account of some practical observations to which it gave rise. 



The calculus was of a brownish colour, soft, and friable, and 

 could be taken from the bladder only in pieces. By exposure 

 to the air it became dry, and owing to the loss of moisture, it 

 became of a browner colour. 



By examining the calculus with potash, acids, and water, 

 nearly similar results were obtained, but the method recom- 

 mended to be adopted is the following : — Ten parts of the cal- 

 culus reduced to powder were heated to the boiling point in an 

 ounce of distilled water; the clear solution was poured off, and 

 the ebullition being twice repeated with a like quantity of water, 

 the solutions were mixed. The insoluble portion was brown, 

 and weighed three parts and a half. 



The solution was of a pale-yellow colour, and when hot red- 

 dened litmus paper strongly, but not when cold ; there were, 

 however, deposited at the bottom of the vessels a great number 

 of small brilliant plates, which were evidently lithic acid ; when 

 dried, they weighed one part. 



The solution evaporated by a gentle heat gave a white, pearly, 

 laminated residuum ; it weighed 4±. parts ; did not redden litmus 

 paper, and on the addition of potash, much ammonia was 

 evolved, and it continued till the whole of the matter was dis- 

 solved. 



The alkaline solution, supersaturated with muriatic acid, gave 

 2 parts of lithic acid ; from this it is to be concluded that the 

 pearly matter obtained by evaporation was lithate of ammonia ; 

 there was also a little phosphate of ammonia. 



The 34 parts of insoluble residuum were heated in muriatic 

 acid, which took up l^- part of oxalate of lime, and this was sepa- 

 rated by ammonia ; the 2 parts insoluble in the acid appeared 

 to be only animal matter ; when burnt, it left only carbonate of 

 lime, and no trace of phosphate of lime; but as the burnt residuum 

 of the entire calculus gave, in a previous experiment, half a part 



