ON WARMING AND VENTILA TION. 329 



little or nothing to add except to say that the art of projecting light 

 by mechanical means seems to have attained a wonderful perfection. 

 There are two branches of this subject which Mr. Stevenson might 

 have mentioned, which he has not done, for want of time. There is 

 the generation of light, either by the combustion of oils, or by electricity, 

 all of which form part of the general subject. There is also the con- 

 struction of lighthouses themselves, but we must be content with what 

 we can practically attain to in collecting information on the exhibits 

 which are here. 



I must therefore ask you to pass a vote of thanks to Mr. Stevenson 

 for his paper. 



The vote of thanks having been carried, 



The PRESIDENT: I will now call on General Morin for his com- 

 munication on ventilation, a subject which no one has investigated 

 more deeply than he has. 



NOTES ON WARMING AND VENTILATION. 



ON VENTILATION. 



GENERAL MORIN, Director of the Conservatoire des Arts et Me'tie'rs 

 at Paris : The subject which I am about to bring before you, cannot be 

 compared with regard to scientific interest to those questions which 

 have already been discussed ; but it affects so closely the well-being 

 of humanity, that it has, for a long time past, attracted public attention. 



Indeed the principles and the results of which I intend to-day 

 giving you some examples, are by no means new. I will do no more 

 than briefly call your attention to them. 



In a work entitled Illustrations of the Theory and Practice of 

 Ventilation, by Dr. Reid, of Edinburgh, and which was published in 

 1844, the principle is already expressed that the introduction of fresh 

 air must take place from the ceiling, and its escape from the floor. 

 The author had applied this system to the Club Room of the Royal 

 Society of Edinburgh. Mr. Goldworthy Gurney, a skilful engineer, 

 had also expressed this principle in these words : " It is desirable 



