156 Intelligence and Miscellaneous Articles, 



IV. Chloride of titanium employed. . 0*716 



Silver 1-61219 



indicating Chlorine 0'52966 



Titanium by difference 0*1 8634 



Equivalent of titanium 31 1*84 . 



V. Chloride of titanium employed. . 0"8085 



Silver 1-82344 



indicating Chlorine 0*59907 



Titanium by difference 0-20943 



Equivalent of titanium 309*38. 



The three first numbers agree perfectly, but the two latter are 

 notably less, especially the last, since it differs from the three first 

 by five whole numbers, or more than 1^ per cent. It was difficult 

 to attribute this difference entirely to deficient precision in the me- 

 thod used. It occurred to the author that it might be owing to the 

 partial decomposition of the chloride of titanium, by the moisture of 

 the air during manipulation, and this was soon found to be the case 

 by direct experiment. 



M. Pierre proposes to adopt, as the nearest approximation to truth, 

 314-69, the mean of the three first experiments, as the equivalent 

 number for titanium. 



This number is very different from 355 deduced from 6-536, the 

 density of the vapour of the chloride of titanium observed by M, 

 Dumas. Its density, calculated from 314-69, would be 6-614. — 

 Ann. de Ch. et de Phys., Juillet 1847. 



ON A MODIFICATION OF THE APPARATUS OF VARRENTKAPP AND 

 WILL FOR THE ESTIMATION OF NITROGEN. BY WARREN DE 

 LA RUE. 



My attention having been called to a communication by Mr. Alex. 

 Kemp in the number of the ' Chemical Gazette' for the 1st of April 

 1847, in which he describes a modification of Messrs. Varrentrapp 

 and Will's tube for nitrogen determinations, of a very similar con- 

 struction to one I employed as far back as November 1845 in the 

 laboratory of the Royal College of Chemistry, and which I have re- 

 peatedly shown to my friends, I am induced to lay before the So- 

 ciety a description of my form of apparatus, which differs somewhat 

 from that described by Mr. Kemp. 



By the drawing, it will be seen that the tube B E, instead of 

 opening immediately into the bottom of the flattened bulb C, is pro- 

 longed and rises for some distance into the bulb curving over to- 

 wards its side ; in this respect Mr. Kemp's apparatus does not differ 

 materially from mine. I found it necessary however to have a third 

 bulb (D) blown (which is best of a spheroidal form), in order to ef- 

 fectually prevent the acid from being drawn into the tube G when- 

 ever a sudden absorption took place ; this third bulb communicates 

 with C by a narrow neck. If the apparatus be constructed without 



