31 



IX. On a Method of Anali/sifig Organic Compounds. By 



Robert Rigg, Esq,, M,RJ,* 



To Richard Phillips, Esq., RR.S. 



Dear Sir, 



tJAVING been so frequently solicited by those who have 



■*• ^ seen me analyse organic compounds to make an early 



and more public communication than I have yet donet of 



the method which I adopt, I beg the favour of your inserting 



in the Philosophical Magazine the following brief account of 



my very simple apparatus, premising that if at any period I 



should publish my researches altogether, I shall then go into 



detail upon this department of chemical manipulation. 



The analytical apparatus consists of two small glass tubes 

 connected by a caoutchouc collar, as shown below. 



C_3= 



l_Ji 



A. A tube, in which is placed the organic compound to be 



analysed, and which for the analysis of one grain is from 

 seven to ten inches in length, and from three to four 

 tenths of a cubic inch in content. 



B. A caoutchouc collar, about an inch in length, in which is 



put a little dry amianthus or cotton wool. 



C. A bent thermometer tube for conveying the gaseous pro- 



ducts to the receivers standing over mercury. 

 The compound to be analysed, a portion of it having been 

 burnt in a platinum spoon with a view to determine the quan- 

 tity of residual mailer, is mixed in the usual way with black' 

 oxide of copper X, varying in quantity from thirty to fifty grains 

 for each cubic inch of carbonic acid gas that will be formed, 

 and varying also with the quantity of water that will be formed. 

 This mixture is put into the clean and dry tube, and upon it 



* See p. 422 of our last volume. — Edit. 



•f A diagram and description of the apparatus was laid before the Royal 

 Society about two years ago ; and the apparatus itself, together with a tube 

 for measuring minute quantities of nitrogen, before the Chemical Section 

 of the British Association in September last. 



I The black oxide, which 1 prepare by burning copper turnings, and not 

 from nitrate of coppery is exposed to a white heat for an hour at least, and 

 well stirred. I afterwards spread it on a plate, where it lies from ten to 

 twelve hours; put it into a bottle, shake it well, and then accurately de- 

 termine the quantity of air and moisture it has condensed ; these remain 

 stationary, when it is kept in stoppered bottles, during the use of two or 

 three pounds of oxide so prepared. [See Dr. Prout*s observations on this 

 subject in Phil. Mag. and Annals, vol. iii. p. 35. Edit.] 



