728 Transactions of the American Institute. 



water, just sufficient to moisten the surface over which the fresh air 

 had to pass on its way into a room, so as to bring into pLay the effect 

 of rapid evaporation. All the details of tlie plans, as applied in the 

 Public School, Rue des Petits Hotels, in the Theatre Lyrique, and in 

 the Conservatoire, were exhibited and explained. by the speaker. The 

 uniformity of temperature in the Theatre Lyrique was a striking result. 

 At a trial in November, when the temperature without was four 

 degrees C, on the stage was nineteen degrees, in the orchestra stalls, 

 twenty-one degrees, in the boxes twenty-three degrees, and in the 

 gallery twenty-three degrees 5 C. This system of ventilation was 

 highly commended by the speaker who followed Gen. Morin. 



The article which elicited most discussion was the suction system 

 of ventilation, as advocated by Gen. Morin, director of the Covsei^a- 

 toire des Arts Metiers, Paris. The economy of the suction system as 

 compared with that of forcing fresh air into rooms by means of blow- 

 ing apparatus was very fully set forth. The amount of fresh air 

 required for each person per hour, in schools, workshops, prisons, hos- 

 pitals and theatres was stated, also the temperature at which the air 

 should be maintained in each kind of building. 



Dr. Warren Rowell gave an amusing description of his experience 

 in a badly ventilated public house. A number of practical questions 

 touching ventilation were raised, and at the close of the debate Mr. 

 Greeley said previous engagement compelled him to retire, and Prof. 

 Tillman assumed the duties of the chair. 



Hussey's Universal Postal Scale. 



Mr. Hussey exhibited his invention, and explained its importance 

 as follows : 



The want of a postal scale that would quickly determine the amount 

 of postage required, to promote accuracy and speed in the transmission 

 of postal matter to all parts of the world, has long been felt by the 

 commercial community. 



It has been the experience of nearly every person having domestic, 

 as well as foreign correspondence through the various posts, that 

 delays and loss of lettei"s in most all instances are. occasioned by 

 ignorance and carelessness in posting communications. Hence the 

 abuse usually heaped upcjn the heads of postmasters and their 

 attachees for (as we think) neglect of duty, when, really, the whole 

 fault lies at our own desks. We should post ourseloes before attempt- 

 ing to post our letters, if we expect them to reach their destinatiou 



