68 Correspondence of Jerome Nickles. 
he has looked forit. The Lat which has led to this wonder- 
result offers nothing new. Let it be added, however, that 
the author referred to areal with os a the purity of which 
he had carefully tested and found to be free from copper. The 
evaporations ane calcinations were performed in a platinum 
n’s burner.* Impressed with this wonderful 
diffusion of a ial which is found everywhere save in the re- 
agents employed for finding it, I could not help recalling the 
process used formerly for the detection of fluorine,j and I 
was led to a like conclusion as regards the diffusion of cop- 
In a word, it appeared to me that there was some source 
of error, and if it was not in the reagents, it must be found in 
the apparatus, sonpein’y the apparatus used for the incinera- 
tion. ‘In fact, the Bunsen burners are generally of copper. 
This metal is said to be volatile when heated in a current of 
gas. Besides, when such a burner is lighted, the flame i is often 
seen colored blue by the copper which is volatilize 
These remarks in my fevue des travauc de Chimie, t are foun- 
ded on facts long since known and utilized in my laboratory, 
and which experiments upon artificial light, with which I have 
been occupied, brought to my attention. They have just been 
confirmed by Lossen,§ who has found that in fact Bunsen’s 
burner is the true source of the copper that has been discov- 
ered in many of the residues from incinerations ; for in exper- 
a phantoms. —In my work on Electro-magnets, I 
have stated a process enabling us to fix and preserve the fig- 
ures — magnets produce when iron filings are subjected to 
_ These figures are known in France by the name of 
phanioms, a name given them by the ace Haldat, of 
ancy. To fix them, the phantoms are developed upon a sheet 
of paper covered over aan wax or stearine, then, a little dis- 
* Jour. prakt. Chem., xcv, 368. ¢ This Jour., II, xxi, 395. 
ce: Jour. de Pharm. etde Ch., IV, ii,412. Jour. de Pharm. et de Ch., TV, iv, 21. 
* 
