ON DUST AND DISEASE. 187 



said that they had not suffered the slightest incon- 

 venience ; that they could have remained all day in 

 the smoke. Captain Shaw then tested the respirator 

 with the same result, and he afterwards took great 

 interest in the perfecting of the instrument. 



Various ameliorations and improvements have 

 recently been introduced into the smoke respirator. 

 The hood of Captain Shaw has been improved upon by 

 the simple and less expensive mouthpiece of Mr. Sin- 

 clair; and this, in its turn, has been simplified and 

 improved by my assistant Mr. John Cottrell. The 

 respirator is now in considerable demand, and it has 

 already done good practical service. Care is, however, 

 necessary, in moistening the wool with glycerine. It 

 must be carefully teazed, so that the individual fibres 

 may be moistened, and clots must be avoided. I can- 

 not recommend the layers of moistened flannel which, 

 in some cases, have been used instead of cotton-wool : 

 nothing equals the wool, when carefully treated. 



An experiment made last year brought out very 

 conspicuously the necessity of careful packing, and the 

 enormous comparative power of resisting smoke irri- 

 tation possessed by our firemen, and the able officer 

 who commands them. Having heard from Captain 

 Shaw that, in some recent very trying experiments, he 

 had obtained the best effects from dry cotton-wool, 

 and thinking that I could not have been mistaken in 

 my first results, which proved the dry so much inferior 

 to the moistened wool and its associated charcoal, I 

 proposed to Captain Shaw to bring the matter to a 

 test at his workshops in the City. He was good enough 

 to accept my proposal, and thither I went on May 7, 

 1874. The smoke was generated in a confined space 

 from wet straw, and it was certainly very diabolical. 



