328 Intelligence and Miscellaneous Articles. 



method of scalars and vectors) enables us, as we have seen, to 

 pass, by a very short and simple symbolical transition, from 

 either to the other of these two great and known properties 

 of the cone of the second degree. 



[To be continued.] 



L. Intelligence and Miscellaneous Articles. 



ON THE DETERMINATION OF CARBONIC ACID IN SALINE COM- 

 POUNDS. BY C. BRUNNER, SEN. 



THE estimation of carbonic acid in its combinations is generally 

 effected by ignition, when the compound is one of those which 

 part with the whole of the acid at a red heat. When water is disen- 

 gaged at the same time, its quantity must either be determined by a 

 separate experiment, and subtracted from the loss experienced on 

 ignition, or collected in a suitable apparatus during the calcination, 

 and so calculated. With those compounds where this method cannot 

 be applied, it is customary to expel the carbonic acid by a stronger 

 acid, for instance sulphuric acid, and to determine its amount from 

 the loss, taking care in this case to retain the water accidentally 

 carried over with it by some suitable substance. Apparatus for this 

 mode of determination have been described by Rose, and recently 

 by Fresenius. 



It is readily seen that, according to these methods, the result is 

 always obtained in a negative manner, that is to say, by a loss in 

 weight. As we should certainly endeavour to exchange all such 

 negative methods for positive, I will here communicate one which 

 appears to me applicable in most cases. The substance to be exa- 

 mined is placed in the little flask a, and a suitable quantity, for 

 instance an ounce, of water poured over it ; upon which the flask is 

 closed with a tight-fitting cork provided with three tubes, and when 

 necessary coated with cement. The straight tube terminates above 

 in a small funnel, through which the sulphuric acid is poured ; the 

 second, provided with two bulbs, is connected by its rectangular 

 bend with a tube b c, from a third to half an inch wide ; and, in 

 order to gain space, likewise furnished with two expansions con- 

 taining asbestos moistened with sulphuric acid; the third is bent 



new, yet it is impossible for him, in mentioning here the name of Chasles, 

 to abstain from acknowledging the deep intellectual obligations under which 

 he feels himself to be, for the information, and still more for the impulse 

 given to his mind by the perusal of that very interesting and excellent His- 

 tory of Geometrical Science, which is so widely known by its own modest 

 title of slperpc Historique (Brussels, 1837). He has also endeavoured to 

 profit by a study of the Memoirs by M. Chasles, on Spherical Conies and 

 Cones of the Second Degree, which have been translated, with Notes and 

 an Appendix, by the Rev. Charles Graves (Dublin, 1841) ; and desires to 

 take this opportunity of adding, that he conceives himself to have derived 

 assistance, as well as encouragement, in his geometrical researches gene- 

 rally, from the frequent and familiar intercourse which he has enjoyed with 

 the last-named gentleman. 



