Constants of Explosion of Cordite and of Modified CorditeAuthor(s): Robert RobertsonSource: Proceedings of the Royal Society of London. Series A, Containing Papers of aMathematical and Physical Character, Vol. 79, No. 530 (Jun. 8, 1907), pp. 320-321Published by: The Royal SocietyStable URL: http://www.jstor.org/stable/92791 .

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320

Constanits of Explosion of Cordite and of Modified Cordite.

By ROBERT ROBERTSON M.A., DUSc.

(Communicated by Col. Holden, R.A., F.R.S. Received January 10,-Read February 8, 1906.)

(Abstract.)

Objects of the Investigcation.-These were to determine, under the conditioins of pressure obtaininc in a gun, the constanits of explosion of cordite and of modified cordite, with special reference to the effects produced by the non- explosive ingredients, mineral jelly anid acetone. The large increase in the percentage of guncotton which characterises modified cordite causes the retentioin of a greater quantity of volatile matter thani was found in the older cordite; the nature of this volatile matter and its effects on the colnstants of explosion are examined.

Appar-atuts and Procedure.-The bomb, made to the design of Colonel Jlolden, F.R.S., at tne Royal Gun Factory, had a chamber capacity of 128-32 c.c., was made of gun steel of about 303 em. in thickness, and was fitted with arrangements for obturation and electrical insulation of the firing-pin and for drawing off the gases, whiclh worked well in practice (diagram- accompanies paper). The calorimeter and miethod of ascertaining the water equivalent of the apparatus are described (diagram), as are also the procedure when a shot is fired (diagrami) alnd the means adopted for collectilng and measuring the gases evolved (diagram).

-Reesults. The results are embodied in a number of tables and include anialyses of the explosive anid of the volatile matter contained in it, the calories per gramme (water liquid and water gaseous), analyses of the gases evolved, the theoretical temperature of explosion (on the basis of the altera- tion of specific heat of the gases according, to the data of Mallard and Le Chatelier), the theoretical pressuire and the heat of formation of the explosives from the elements at constanit pressure.

Calculations of the heat developed by the explosive are made from the h-eats of formation of the constituents of the explosive and products of its decomposition, and it is shown that the results so obtained are in good agreement with the actual calorimetric results. For the purpose of this calculationi a special determnination of the conistants of Waltham Abbey gun- cotton was inade.

Consequent oni the change in comiiposition] froma corclite to modified cordite,

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Constants of Explosion of Cordite and of Modifed Cordite. 321

the following are among the differences brought out, namely, a decrease in heat of 200 calories, and in temperature of explosion of 3000 C.-facts which have a bearing on the decreased erosion found with the latter explosive-an increase in volume of gas and changes in the character of the gases.

The effect of the presence of mineral jelly in both natures of cordite is examined, as to the great diminution of heat, increase in voluime of gases, etc., that result.

In a similar way the effect of the varying quantities of volatile mnatter found in modified cordite is ilnvestigated as to the constants of explosion. It is shown that in the modified cordite actually rmade the water in the volatile matter is practically constant, variations being due to acetone retained. Decrease in heat evolved, increase in gases and differences in comiposition of these gases due to the presence of acetone, are some of the results brought out in this part of the work.

Note is also made of the alterations in the constants of explosion due to increasing the density loading from 01 to 0-2.

VOL LXXIX.-A. Z

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