360 On Experiments with a Fireman's Respirator. [May 21, 



respirator. My first trials were made with cotton-wool alone. Asso- 

 ciated with the respirator was a mouthpiece with two valves : through 

 one the inhaled air reached the lungs, having first passed through the 

 cotton-wool, while through the other the exhaled air was discharged di- 

 rectly into the atmosphere. The smoke was generated in small rooms, 

 and in some experiments in a cupboard ; but though the irritation of 

 the smoke was greatly mitigated by the cotton-wool, it was unbearable 

 for any considerable time. 



The cotton-wool was next carefully moistened with glycerine, no clots 

 which could intercept the air being permitted. The respirator was 

 distinctly improved by the stickiness of the fibres of the wool : still, when 

 the smoke was very dense, an amount of irritation continued, which 

 materially interfered with the usefulness of the respirator. Thinking it 

 certain that the mechanically suspended matter would be intercepted by 

 the moistened wool, I concluded that this residual irritation was due to 

 the vaporous hydrocarbons generated during combustion : hence the 

 thought of associating with the cotton-wool Dr. Stenhouse's excellent 

 device of a charcoal respirator. The experiment was successful. With 

 this combination it was possible to remain with comparative comfort 

 for half an hour, or even an hour, in atmospheres a single inhalation 

 of which without the respirator would be intolerably painful. 



Captain Shaw, of the Metropolitan Fire Brigade, has worked ener- 

 getically towards the completion of the respirator by associating with it 

 a smoke-cap. Mr. Sinclair has done the same, and he informs me that 

 the respirator is now in considerable demand. 



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 the 7th of May. The smoke was generated in a con- 

 fined space from wet straw, and it was certainly very diabolical. At this 

 season of the year I am usually somewhat shorn of vigour, and there- 

 fore not in the best condition for severe experiments ; still I wished to 

 test the matter in my own person. With a respirator which had been 

 in use some days previously, and which was not carefully packed, I fol- 

 lowed a fireman into the smoke, he being provided with a dry-wool 

 respirator. I was compelled to quit the place in about three minutes, 

 while the fireman remained there for six or seven minutes. 



I then tried his respirator upon myself, and found that with it I could 

 not remain more than a minute in the smoke ; in fact the first inhalation 

 provoked coughing. 



Thinking that Captain Shaw himself might have lungs more like mine 

 than those of his fireman, I proposed that he and I should try the 



