430 Correspondence of J. Nickles. 
ner to plates previously exposed to the sun. We give a résumé of the 
new results in two memoirs esteemed by the Commission worthy of re- 
Ww . 
tive is obtained. : 
In this process the manipulation is a little easier and more simple. 
The use of a negative authorized the expectation of a better result, but 
the exposure is longer than in the mode of Garnier and Salmon, whose 
use of a positive avoids the chances of accident which attend the nega 
tive plates in the hands of the operatar. oe 
Messrs. Pouncy, Garnier and Salmon share the prize with Mr. Poiteri, 
who has the merit of anticipating these photographers, whose methods 
are only an advance on the process which Mr. Poiterin published in 1856. 
ormation of cellulose into sugar—We have already spoken in 
* This volume, page 126. 
