560 



Robert Ball, Esq., was elected Treasurer of the Academy, 

 in the room of James Pirn, Jun., Esq., who resigned. 



Dr. Apjohn read a paper by Mr. Thomas Knox, " On 

 the Purification and Ventilation of Vessels from bad Air." 



In reperusing lately Professor Daniell's interesting re- 

 searches* " on the spontaneous evolution of sulphuretted 

 hydrogen in the waters of the western coast of Africa and 

 of other localities," a method occurred to me of purifying the 

 cabins of vessels, and the sleeping apartments in houses, 

 which would be as efficacious as Professor Daniell's, with- 

 out being liable to the objection of having free chlorine 

 always present producing its enervating effects. 



The method I propose is this : to have air pumped 

 through tubes extending from the steam engine to the cabins. 

 The extremities of the tubes should dip into vessels contain- 

 ing solutions of chlorine or metallic solutions ; the last solu- 

 tion, being of lead, would indicate when the solutions were to 

 be renewed, by the black precipitate of sulphuret of lead. 

 At the further end or top of the cabins there should be cor- 

 responding tubes to allow the foul air to be removed ; these 

 latter would be unnecessary when there was a fire, the draft 

 being sufficient to remove the foul air. 



As we can absorb or destroy all vapours, miasma, &c., 

 this method would apply to all unhealthy regions of the 

 world, and would render habitable parts of the world which 

 at present lie deserted and waste. Sierra Leone would cease 

 to be the grave of Europeans, and the Pontine Marshes 

 would no longer exhibit a ghostlike peasantry. 



EXPERIMENTS. 



Chambers made of wood, with air-tight windows, having 

 apertures in the sides, into which the tubes would fit, could 



* Phil. Mag., July, 1841. 



