1824.] Royal Society. 459 



Prof. B. has confirmed the results obtained by M. Arfwedson, 

 and also Mr. Phillips's discovery of phosphoric acid in the 

 uranite. He has examined the uranite of Autun, and also that 

 of Cornwall : finding the former to be a phosphate of uranium 

 and lime, and the latter a phosphate of uranium and copper; 

 the number of atoms of water being the same in both. The 

 third contains an examination of a mineral in an old collection 

 at Stockholm, labelled ' from Mendip, near Churchhill, in So- 

 mersetshire.' This substance consists of I atom of chloride 

 of lead, and 2 atoms of oxide of lead, and also contains car- 

 bonate and molybdate of lead. It is distinct from the murio- 

 carbonate of Matlock. The fifth memoir relates to the combi- 

 nations of fluoric acid. A portion of this memoir now printing 

 describes a method by which the author has succeeded in ob- 

 taining the base of silica in an insulated state. It consists in 

 acting by potassium on dry silicated fluate of potash, by which 

 means a mixture of various substances is obtained, which yields 

 hydroguret of silicon by being well washed with water : and 

 when that substance is heated in a crucible the hydrogen is 

 burned oft", and the silicon obtained pure. Prof. B. then pro- 

 ceeds to give the results of various experiments upon this 

 substance ; among which are the following. It is obtained in 

 various states of aggregation, and its combustibility varies ac- 

 cordingly, it much resembling carbon in this respect : as usually 

 obtained it is combustible when ignited in atmospheric air and 

 in oxygen gas ; but in its dentsest state it may become incan- 

 descent in the air without burning. It is very difficult to effect 

 its complete combustion : 200 parts of silicon unite to 208 of 

 oxygen to become silica. It will not burn when heated with 

 nitre, but is brought into combustion by carbonate of potash ; 

 a curious circumstance which the author attributes to certain 

 relations of affinities. Silicon burns when ignited in chlorine, 

 forming with it a transparent colourless fluid, having the smell 

 of cyanogen. It is combustible in vapour of sulphur, producing 

 a grey sulphuret, but cannot in this case be completely burned. 



Prof. B. next describes the results of the same mode of 

 decomposition as applied to ittria, glucina, and zirconia ; giving 

 the chemical habitudes of zirconium, which can be obtained 

 in larger quantities than the bases of the former earths. He 

 then states that he has used the term Jiuate instead of jiuoride 

 throughout this letter, not because he thinks the President's 

 ingenious theory on the subject less probable than his own 

 (though he has not been able, by his own experiments, to de- 

 termine which is the true one) ; but because, as he was writing 

 in a language foreign to him, he wished to employ the plainest 

 terms : and concludes by requesting Sir Humphry to lay the 

 above results before the Royal Society. 



The reading was commenced, of a paper " On some new 

 phamomena effected by magnetic influence, by J. II. Abrahams," 

 of Sheffield : communicated by Mr. Tooke, FRS. 



