IX. Researches on Explosives.—Part I IV* 
By Sir Andrew Noble, Bart., K.C.B., D.Sc. 
(Oxon.), D.C.L., F.R.S. 
Received June 28,—Read June 28, 1906. 
[Plates 10-19.] 
In Part III. of my ‘ Researches on Explosives’ I gave the results of a very extensive 
series of experiments, the completion of which necessarily occupied a very long time, 
and the particular explosives with which I experimented were those with which 
artillerists in this country were familiar, and with which a considerable number of 
experiments had been made. 
These explosives were (1) the cordite of the service known as Mark I; (2) the 
modified cordite known as M.D. ; and (3) the nitrocellulose known as Ptottweil R. R. 
The experiments made by myself extended, for all the above explosives, from 
densities of 0'05 to 0-'45 or 0 - 50, and pressures of from 275 tons per sq. inch (419 
atmospheres) to pressures of 60 tons per sq. inch (9145 atmospheres), and although 
the transformation on ignition varied both with regard to the particular explosive 
employed and for each explosive as regards the density at which it was fired, yet 
when the observations were represented by curves drawn through or near the 
observed points there was a pretty close resemblance in the form of the curves, not 
only in respect to the variations in the quantities of the gases generated at the varied 
densities, but also with regard to the units of heat developed and the volumes of gas 
produced. 
Certain anomalies, chiefly with reference to the temperature of explosion at 
different densities, having appeared, I was anxious to make experiments with other 
* Small alterations are required in some of the figures given at the higher densities, owing to experi¬ 
ments which have been carried out at a density of 0 • 50 since the paper was prepared. The curves, 
however, have all been corrected to the later results. 
VOL. COVI.—A 410. 
13.10.06 
