Determination of Nitrogen in Organic Compounds. 259 



composing the chloride of platinum and ammonia by heat. They 

 therefore recommend that the spongy platinum used to form the 

 chloride, should be well washed with hot distilled water, before 

 being dissolved in the nitro-hydrochloric acid. 



'' If we weigh the nitrogen as the chloride of platinum and 

 ammonia, we have one hundred and seventy seven parts of it for 

 every two thousand seven hundred and eighty eight of the double 

 chloride, but if as metallic platinum, one hundred and seventy 

 seven parts for every twelve hundred and thirty three of the 

 metal." 



" The weight of the chloride of platinum and ammonia remains 

 constant under a long continued drying at' 212° Fah., as well as 

 that of the filter, after it has been completely washed. If there 

 be a trace of acid remainmg on the filter it becomes dark and 

 friable." 



I believe that now all the important steps in this operation have 

 been fully detailed, and I shall conclude with a translation of a 

 letter of Prof. Liebig's, that was attached to the original publica- 

 tion, in order that it may be seen, how highly this new method of 

 estimating the quantity of nitrogen in organic bodies is esteemed 

 by that distinguished chemist. 



"I have had the pleasure of being constantly present at the 

 development oi the experiments by which Drs. V. and W. by 

 degrees have arrived at the method, which they have here de- 

 scribed. I regard this new method of estimating nitrogen as one 

 of the most important improvements in organic analysis, because 

 it determines the quantity of nitrogen with a certainty and pre- 

 cision which until now were wanting. The whole opreation is 

 completed in a few hours, and with all the accuracy of the deter- 

 mination of the carbonic acid. I doubt not that this apparatus 

 will very soon replace the ordinary method, to the contentment 

 of all analytical chemists. — J. L." 



The little experience and observation I have had of it, verify 

 the opinion of Prof. Liebig, and in simplicity it is every thing 

 that can be desired. 



Geissen, November, 1841. 



