204 SIE ANDREW NOBLE: RESEARCHES ON EXPLOSIVES. 



can be brought to any point of the thermometric scale that may be desired. The 

 temperature can be read approximately to O'OOl C. 



Full illustrations of a few of the calorimetric observations will be given with the 

 corresponding calculations, and a resume of the results of the experiments at the end 

 of the paper. 



The analysis of the gaseous products of explosion was carried out by means of 

 SODEAU'S gas analysis apparatus,* the principal features of which are shown in 

 Plate 3. 



Mr. SODEAU'S apparatus is admitted to be the most convenient that has been yet 

 devised. I am indebted to him for the description of his apparatus and the mode of 

 analysis followed. 



The tubes used for measuring and correcting for variations of temperature and 

 pressure are placed in a cylindrical water-jacket. The measuring tube M is of 

 50 cub. centims. capacity, and is graduated in -^-cub. centirn. divisions. Its upper 

 end terminates in a capillary three-way stop-cock N, arranged so that the capillary K 

 may be placed in communication either with the interior of the measuring tube or 

 with the bent tube U containing water. The zero point of the graduation is at the 

 outer side of the plug of the stop-cock N. The level tube L communicates with the 

 measuring tube by means of a side branch, bent so as to prevent any entangled air 

 bubbles from reaching the measuring tube. The lower end of the level tube is 

 connected to a T piece, one end of which is provided with a stop-cock and leads to 

 the mercury reservoir, whilst the other is prolonged across the table to a point near 

 the reading telescope, where it terminates in a piece of thick-walled rubber tubing, 

 the compression of which by a broad screw clip affords a means of accurately adjust- 

 ing the level of the mercury without taking one's eye from the reading telescope. 



In order to render the apparatus more compact, the reading telescope is placed on 

 the gas analysis table instead of on a separate support, and all graduations are 

 consequently on the side opposite to that from which the stop-cocks are manipulated. 

 An illuminating arrangement slides on the rod P. 



The corrections for variations of temperature and pressure are found by means of 

 the "Kew Principle" correction tube C, which is so called because, as in the " Kew " 

 barometer, the disturbance of the level of the liquid is allowed for in the graduation 

 of the instrument, instead of being adjusted before each reading is taken. It 

 consists of a cylindrical bulb having a stop-cock at its upper end, and attached below 

 to a U tube, which is graduated on one limb and filled with water up to the zero 

 mark whilst the stop-cock is open. The volume of air contained in the bulb is such 

 that the water is displaced to the extent of one small division by a change of 

 temperature and atmospheric pressure, which will cause a gas to experience an 

 alteration of volume amounting to O'l per cent. These small divisions are further 



* 'Journal of the Society of Chemical Industry,' Feb. 28, 1903, page 187. 



