398 InteUiaeiice aiid Miscellaneous Articles. 



"ts 



The density of its vapour was found to be 7*18 ; calculation gives 

 7'234, admitting that SiOC'»H^O represents a volume of the vapour; 

 this mode of condensation has not been hitherto observed in com- 

 pound aethers. 



On receiving in separate portions the product distilled betvv'een 

 338° and 570°, it was found by analysis that the carbon and hydro- 

 gen were constantly in the same proportions in the sether, but the 

 proportion of silica increased with the temperature. The liquid di- 

 stilled at above 570° is colourless, and has a weak smell and a taste 

 different from that of the sether above described. Its density is 

 1*035. The action of water and of the alkalies upon this compound 

 is perfectly similar to that upon the aether, SiOC''H''0 ; its analysis 

 indicates its formula to be (SiO)-C^H^O. 



Silicic acid forms then at least two gethers, and their formation is 

 readily explained by the two following formulas : 

 SiCl + C*H''0'i=HCl + SiOC4H^O, 



(SiCl)2 + 2C4H60^=:C^H'Cl-j-HCH-HO + (SiO>C4H^O. 



It is to be remarked that, during the reaction of alcohol on the 

 chloride of silicium, hydrochloric acid is disengaged only as long as 

 the chloride is excess ; and it is only when the last portions of alcohol 

 have been added that hydrochloric cEther can be obtained. Accord- 

 ing to the formulas, 1 equivalent of alcohol, 575, must be employed 

 for 1 equivalent of chloride of silicium, 535 ; and these were the pro- 

 portions of these two bodies, which were, in point of fact, made to 

 act upon each other. 



The author has tried the action of alcohol upon the chlorides of 

 tin, titanium, arsenic and phosphorus, the results of which he intends 

 to lay before the Academy. — Journ. de Pharm. et de Ch., Octobre 

 1844. — 



TRIGONOMETRICAL NOTATION. 



Mr. Drach proposes the following : — 



sin -^0", cos '^x, &c. for arc (sin sz x) = cos~-^ (x — ^w), &c., 

 and sin~ ^ x being legitimately 1 -i- sin x, and so forth. 



CORRECTIONS IN THE TRANSLATION OF M. WARTMANN's PAPER, 

 IN OUR LAST NUMBER. 



The best thanks of the Editors are due to their Glasgow corre- 

 spondent who signs himself " A Subscriber," and who directs their 

 attention to some oversights in the translation of M. Wartmann's 

 paper, contained in the last number of the Philosophical Magazine. 



In p. 269, 



should have been printed thus, 



T = eqV~7~J. 

 P. 272, line 23, for " currents in contrary directions," read " cur- 

 rents in the same direction." 



