l94 • journal of the Asiatic Socieiij of bengal. [April, 1907. 



1 



positive and negative ions contained in the generated gases. The 

 reactions hitherto dealt with have been tlie evolution of oxygen 

 by the heating of various solid substances. The apparatus used 

 18 shown diagramatically in the figure below. A is a slightly 

 bent liard-glass tube in which the substance to be decomposed was 

 heated by means of a bunsen burner. G is a plug of glass wool to 

 prevent the passing over of any solid particles. BB are two 

 ebonite tubes supporting and insulating the brass tube D, along 

 whose axis an insulated rod TT is supported at S. Both TT and the 

 inside of the tube D were silver-plated, in order to afford con- 

 stantly clean surfaces. The insulation of TT offered some diffi- 

 culty in tins climate, but was finally effected by means of sul- 

 phur with the help of an earthed guard-ring R. The outer tube 

 JU could be charged up either positively or negatively to about 

 ^bO volts by means of 140 of Pye's small storage cells. This was 

 tested and found to be more than the saturating voltage required 

 to extract all the ions from the gas. The method of makincr an 



itlrontnairof ^:''i^'^r'\'^^^""^"^ ^°^ '^^^ ^^^^ ^^-- *« connect 

 It to one pair of quadrants of a Dolezalek electrometei- So lone, 



^Zrt f elT ^'"^' ''™"«^ *^^ ^^^^ *^^ -'die rema n f 

 the roi bv ions o^'^.i;'^' proportional to the charge given up to 

 knowbJ^theT.L . /!^''^^^' *^" ^^^^ might be. Thence. 

 wrSml eT bT't.re method ^f ^.^^^--^^^ ^^^^em (which 

 capacity) and J^L^L^ttt^^'^'''''' with a measurable 



?he t^taf Tm? "of i:n "a'T '''J.'^^' '' t '^'^ '' ^^^^^^^*^ 

 metre. Weighed quantities of ^^ ^.^^^ °"«ber per cubic centi- 

 so as to afford the^s^e tolm *^? ''^"-"' substances were taken 

 stances were the Trnilnlanltf ^tV"" f^'^ r"- These sub- 

 potassium, the peroxTdroTSni'. at^lt;uHc'oS'^°^^*^ "' 



^ 



r 



