TRANSACTIONS OP THE SECTIONS. 



n 



The foUowing Tables exhibit the results of foi-ty-eight day experiments : — 

 Table I.— Uric Acid and Carbonate of Soda (Sod. Carb. Exsiccat. of the shops). 



Table II. — Uric Acid and Carbonate of Potash. 



Strength of the 

 solution. 



Flow per 

 24 hours. 



No. of 

 Obs. 



Daily average loss of 

 weight per cent. 



Remarks. 



240 grains per 

 pint. 



120 



6 pints 

 6 „ 







80 



60 



60 

 40 



30 

 30 

 30 

 30 

 20 

 10 



14 







15 

 8 

 4 

 6 

 6 

 6 



2 



2 



5 

 3 



4 

 2 

 2 

 4 

 3 

 3 



9-8 



19-01 

 21-4 



20-2 



15-6 



11-9 



Covered with a tena- 

 cious white coat as if 

 of paint. 



Covered with a less 

 dense coating. After 

 detaching this and 

 vriping, there was a 

 loss of weight of T'l 

 per cent. 



Covered with a loosede- 

 tachable white crust. 



Surface clean. 



Loose flakes in spots. 



Sometimes a few loose 

 flakes where the frag- 

 ment rested. 



Dissolved clean : occa- 

 sionally a few loose 

 flakes. 



Dissolved clean. 

 Dissolved clean. 



On Perchloric Acid and its Hydrates. By Professor Roscoe, 



AH the knowledge we possess of the quantitive relations of perchloric acid is the 

 detei-niination of the composition of the potassium salt, first analysed by Stadion, 

 1816, and afterwards by many other chemists. The perchloric anhydi-ide has not 

 been isolated, and no analysis of the aqueous acid has ever been made. We can 

 only account for the neglect with which chemists have treated the highest and yet 

 the most stable of the oxides of chlorine by the fact that the preparation of the 

 acid in larger quantities has been attended with great difficulties. The best method 

 for preparing aqueous perchloric acid is to decompose chlorate of potassium with 

 hydrofluosUicic acid, and to boU down the chloric acid thus obtained ; this splits up 

 into lowey oxides of chlorine, which escape in the gaseous state, impure perchloric 



