Chemical Notices : — M. Mitscherlich on Spectrum Analysis, 519 



so that we have 



x ( «-,)(ns-my) 



px — OOJ 



fix— ay 



as the equations of the generating line which passes through the 

 point (x, y) of the cubic curve. 



2 Stone Buildings, W.C., 

 October 28, 1862. 



LXXI. Chemical Notices from Foreign Journals, 

 By E. Atkinson, Ph.D., F.C.S. 



[Continued from p. 390.] 



MITSCHERLICH has contributed* an article on spectrum 

 analysis, in which he describes a method for obtaining 

 a constant and intense coloured flame of any particular substance. 



A tube closed at the top, but drawn 'out and somewhat bent 

 upwards at the bottom, contains a solution of the substance to 

 be investigated. The shape of the tube is like that of a Cooper's 

 mercurial receiver. In the drawn-out part a bundle of very fine 

 platinum wires is placed, projecting somewhat out of the tube. 

 This platinum wire is placed in the flame of a Bunsen's burner, 

 and the bundle of platinum wires, in virtue of capillary attraction, 

 remains filled with the liquid, which replaces that which has been 

 evaporated. When the tubes have been in use some time, the 

 bundle of wires becomes choked up with substance, which thereby 

 prevents the absorption of any more. To retain the capillarity, 

 acetate of ammonia is added to the solutions to be examined. 

 This, on burning, disperses the substance under investigation, 

 thereby producing an intense and constant flame. A mixture of 

 20 parts of a solution of 15 per cent, of acetate of ammonia, 

 and one part of the strongest solution of the salt, is found to be 

 the best. Attention must be paid to the position of the platinum 

 wires, in order that neither too much nor too little liquid 

 reaches the flame. 



A series of such tubes containing different substances may be 

 arranged on a stand like those on which pipettes are supported, 

 and brought at pleasure into the flame. The apparatus when 

 not in use may be placed under a glass jar, so as to protect the 

 solutions in the wires from evaporation. The size of the vessels 

 used by Mitscherlich gave a flame which was perfectly bright 

 and lasted for two hours. 



* Poggendorff's Annalen, July 1862. 



