.1814.] On the Ccnfte of Ch-vnical Proportions. 251 



8. Titanhnn. (Ti). — Richtcr found, (Neue Gegcnstande Cah. 10, 

 p. li'O,) that a solution of muriate of titanium, which contained 

 S-l"l of oxide of titanium, gave 150 parts of muriate of silver; 

 and though we cannot put much confidence in the accuracy of this 

 chemist, I thought it worth while to notice the experiment, as fur- 

 nishing at least an approximation. According to it, 100 muriatic 

 acid combine with 295'2 of oxide of titanium ; that is to say, that 

 the white oxide of titanium contains very nearly 10 per cent, of 

 o.xygen. But if the copper coloured oxide be '1 i + O, the white 

 oxide ought to be Ti + 2 O, and the volume of titanium ought to 

 neigh 1801. I must observe however, that Vauquelin lays it 

 down as proved by his experiments, tliat the white oxide contains 

 00 red oxide and 10 oxygen. But there is reason to conclude, that 

 his white oxide contained potash. 



i). Zirco7ii/n7j. (Zr). — Unknown. 



10. Silkium. (Si). — In my experiments to reduce silica by 

 means of iron and charcoal, I found that when the alloy of iron 

 and silicium dissolved in muriatic acid, the silicium combines with 

 a great quantity of oxygen. And after having determined the 

 quantity of red oxide of iron, of carbon, and of silica produce^ 

 by the decomp(;sition of the alloy, 1 considered myself as entitled 

 to conclude, that silica contains from Ab-?A to 47'7S per cent of 

 oxygen. Mr. Stromeyer, who has repeated these experiments with 

 a good deal of care, has found by an analytical method different 

 from mine, that silica must contain as much as 55 per cent, of 

 oxygen. It appears that the best way of determining the compo- 

 sition of this earth , would be to calculate it from the fiuate of 

 silica ; but the composition of this acid being only known from 

 that fluate, we cannot employ this method here. 1 have already, 

 'fvhcn treating of fluoric radicle, made observations on this subject, 

 and have cited the ingenious experiments of JNIr. John Davy, on 

 several combinations of fluoric acid. Among these experiments, 

 there is one wliich may be of use to us here : I mean the analysis 

 of triple fluate of silica and ammonia. According to Mr, John 

 Davy, it is composed of 2-1 "5 ammonia, 40-357 silica, and 

 21'" 143 fJuoric acid. Novy it is necessary, that the oxygen of the am- 

 monia, which is here the smallest quantity, should exist in the silica, 

 mu!ti]>lied by a whole number. But 2t-5 of ammonia contain 

 ll'jrjof oxygen, and the silica (supposing it to contain 48 per 

 cent, of oxygen), contains in 4G-'6'u parts, 22"35 of oxygen. But 

 Il"219 X 2 = 22-438. From this it would appear, that the re- 

 sult of my experiments is not very far from the truth, while it is 

 impossible for silica to contain so much as 55 per cent, of oxygen, 

 uiilc<is the experiments of Mr. Davy be very inaccurate, which I 

 have no reason to believe. Another maimer of verifying the com- 

 ])o*ition of silica is to examine, with more care than is usually 

 done, the composition of the minerals of wliieh it constitutes an 

 ingredient, and in which it must be comhined with the otlier con- 

 ititucnts, according to the laws of chemical proportions. VVs 



