960 ON DYNAMITE. 
cent. of nitro-glycerine, and owes all its power to that ingredient, 
we can to some extent explain the symptoms which inhalation of 
its gaseous compounds after explosion produces, by a reference to 
the chemistry of nitro-glycerine. And so we find, in practice, 
that complete explosive decomposition originates no very unpleasant 
effect. It is, however, rare that complete explosive decomposition 
occurs. Miners wil] overcharge the holes, and portions of the 
dynamite distant from the cap are resolved, not into the simple 
carbonic acid, oxygen, aqueous vapour, and nitrogen, but into 
higher organic compounds, such as acrolein, oxalic acid, hydro- 
eyanic acid, and oxides of nitrogen. Dr. Gladstone has suggested 
that the acrolein is more likely to come from traces of glycerine 
which have neither been converted nor washed out, than from 
pure nitro-glycerine. Miners who employ dynamite complain of © 
head-ache—a peculiar pain in the back of the head, or upper part 
of neck—and, briefly, affections of the mouth, eyes, larynx, throat, 
and lungs, indicative of the inhalation of some irritating vapour. 
It is not necessary for me to give particulars, in detail; I may add, 
however, that a great many diseases are attributed to dynamite 
where, on careful inquiry, we cannot discover a trace of connexion. 
I believe acrolein, or acrylic aldehyde, to be the head and front 
of the offending. It is a complex organic compound, found in large 
quantities during the distillation of glycerine, and has received 
its name from its intensely irritating effects upon the mucous 
membrane of the eyes and organs of respiration; and I am 
indebted to Mr. S. J. Rowe, of Redruth, not only for the sugges- 
tion, but for the trouble kindly taken in going underground with 
me and, by means of test solutions, air-pump, and suitable appar- 
atus, verifying the fact. 
Mr. Bottomley, assistant to Sir Wm. Thompson, the Professor 
of Natural Philosophy in the University of Glasgow, in correspond- 
ence with me has suggested the use of respirators, so as to get rid 
of the vapours complained of. He writes that Mr. Whitehouse, 
the electrician, has made respirators of caustic potash for men 
working in a factory where large quantities of nitrous fumes were 
given off, and that complete protection was given. Potash would 
also neutralize the acrolein. Such respirators could be made for 
a few pence, and no doubt would prove effectual. Dr. Gladstone, 
in a letter to Mr. Bottomley, asks “what would be the effect of 
