OF HIGH EEFEAN GIBILIT Y UPON GASEOUS MATTEE. 
3G3 
After four minutes’ action a number- of -coarse particles had formed in the tube together 
with a faint scroll of cloud. The action was very feeble. For vigorous action with the 
nitrite of butyl the proportion of the acid to the vapour must be large. 
The hydrochloric acid here employed was that ordinarily used by chemists in quanti- 
tative analysis. The same series of experiments was executed Avitli commercial hydro- 
chloric acid ; the action in this case Avas distinctly more energetic than when the pure 
acid was employed. 
Hydride of Caproyl (C 6 H n G, H) : — A transparent colourless liquid. 
Contents of experimental tube. 
Air and hydride of caproyl ..... 8 inches. 
Air and nitric acid ........ 8 inches. 
The tube Avas optically empty at starting. In three quarters of a minute a blue cloud 
had formed throughout the tube. It remained perfectly polarized for three minutes ; 
then became gradually Avhite, discharging imperfectly polarized light. At the end of 
ten minutes a dense Avhite cloud filled the tube. 
§ XIII. 
I thought it worth while, for the sake of bringing out the influence of vibrating period, 
to contrast the action of powerful foci of dark rays with the feeble foci produced by 
the convergence of the more refrangible rays of the spectrum. It is known that the 
dark calorific rays pass freely through a solution of iodine in bisulphide of carbon ; such 
a solution Avas employed to hold back the luminous part of the electric beam. A cell 
containing ammonia sulphate of copper was employed to hold back the rays of Ioav 
refrangibility and allow those of high refrangibility transmission. The destructive action 
of the ammonia sulphate in the calorific rays is well known. Its depth in the present 
case Avas such as to quench completely the red, orange, and yellow of the spectrum, but 
it allowed transmission to the violet and blue, and a small portion of the green. The 
vapours employed Avere mixed with the various acids mentioned. 
Nitrite of amyl _. t . o . 8 inches. 
Pure hydrochloric acid . . 8 inches. 
The convergent beam of the lamp was sent through the cell containing the solution of 
iodine, and Avas permitted to act upon the mixed acid and vapour for ten minutes. The 
ammonia-sulphate cell Avas then introduced and the opaque solution removed. For an 
instant afterwards the tube Avas optically empty. Then a dense cloud Avas precipitated, 
which advanced like a moving share toAvards the most distant end of the tube. Within 
half a minute after the withdrawal of the opaque solution the tube was filled Avitli cloud, 
which augmented in density for five minutes, when the experiment ceased. A repetition 
of the experiment yielded the same result. 
