BAIRD &TATLOCK (LOM)ON) LTD. 



3623 



Apparatus for testing nitro-glycerine, as devised by Dr. R. Robertson, Research Department, 

 Royal Arsenal, Woolwich. 



>15 Horseshoe-shaped tube, with double spirals of glass 

 1 16 Copper bath for heating the above, on stand 

 >17 Jena glass combustion tubes for copper asbestos 

 18 Small furnace with five Bunsens for heating above 



19 Spiral glass condensing worm, with ground joints and cooling jacket 

 i20 Observation tube 



21 Spectroscope, with dense glass prism and camera attachment . . 



22 Wills' gas measuring tube, as Fig. 3624, with auxiliary tube and I.R. tubing 



23 Complete apparatus as above 



DESCRIPTION OF APPARATUS. 



Jena glass wool, soaked in 0.3 to 5 gr. nitro-glycerine dissolved in acetone, which is subsequently evaporated 

 , is placed in the horseshoe-shaped tube, closed by a greased and mercury-sealed plug. A current of CO, can 

 sent down the right-hand spiral, through the glass wool, and up the other spiral, or vice versa, according to 



- position of the stopcocks. At the upper end of the apparatus is a slip joint, between which and a supporting 

 "t at the bottom the whole apparatus can be rotated about its axis. The CO, used contained only 0.02 per 



M. of gas unabsorbed by KOH solution, and, to eliminate any oxygen, was passed over red-hot copper asbestos. 

 iral S l is immersed in an oil bath, the temperature of which is known, and is maintained uniform by a stirrer. 

 serves as a preheating worm for the CO a . Spiral S 2 is above the heated oil, is protected from it by asbestos 

 rds, and is cooled by an air-blast. It serves to condense any volatilised nitro-glycerine. After a suitable 

 rind the apparatus is rotated through 180 degrees, when the spirals exchange functions. Any nitro-glycerine 

 uch has condensed in S 1 is now restored to the system. The gaseous products of combustion are led off for 

 amination through the slip joint by means of fixed glass tubes, the use of indiarubber being thus avoided. 

 a precaution against the carrying over of nitro-glycerine, the gases pass through an ice-cooled worm imme- 

 itely on leaving the decomposition apparatus. The mixture of CO.,, of which the volume is known and rate 

 iform, and volatile products of decomposition was usually passed through an observation tube, in which the 

 icentratiou of NO 2 was determined by the spectroscopic method of Robertson and Napper C/-C.S., 1907, xci. 

 i), and from this the weight of nitrogen disengaged in the form of NO, was calculated. In most cases the 

 issuing from the observation tube were then passed through hot reduced copper asbestos and copper oxide 

 tos, and into a gas burette containing caustic potash solution, where the unabsorbed nitrogen is measured 

 Tter of an hour. The weight of nitrogen is calculated after deduction of the amount contained in the 

 the rate of which was uniformly 1,000 cubic centimetres per hour. 



The Ilford chromatic plate is the most suitable for taking photographic records. 

 See Journal Chemical Society's Transactions, 1909, part 2, page No. 1243. 



17 6 

 1 10 

 026 

 18 

 086 

 076 



17 10 

 1 13 



23 5 



-i 



(CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS. 



679 



