.258 Proceedings 



[abstract.] 



The speed with which smell is propagated through air was inves- 

 'tigated for some substances by letting the smell pass through tubes 

 where the disturbzing influence of convection currents in the air is 

 practically avoided. 



It was found that the speed is quite small, showing that the rapid 

 propagation ordinarily observed in free space is due almost entirely to 

 convection currents. For example with ammonia diffusing through a 

 glass tube 1.5 meters long and .76 cms. in diameter, over two hours 

 elapsed before the smell could be detected at the other end of the tube. 

 With different lengths of tubing it was found for ammonia and hydro- 

 gen sulphide that the time required for the diffusion of the smell was 

 roughly proportional to the square of the length. 



The presence of ammonia could be detected chemically at a given 

 point in a tube in about the same time as when the sense of smell 

 was used for a detector. 



The rate of propogation of the smell of ammonia was not markedly 

 dilTerent when this had to pass along the same tube either horizontally 

 or vertically upward or vertically downward. With camphor, how- 

 ever, while the rates horizontally and vertically downward were about 

 the same, the speed upward was about twice as great. 



The smell given to brass and iron by rubbing them with the fin- 

 gers was also tried but gave no definite results. 



Professor O. W. Oestlund gave a review of recent ento- 

 mological literature, speaking especially upon some papers by 

 Marie V. Linden on pigments of Lepidoptera. 



267th Meeting, April 11, 1904. 



Geology Lecture room, University of Minnesota. 



Thirty persons present ; President Hall in the chair. 



Pursuant to notice at last mecLing the yearly dues of resi- 

 'dent members were reduced from $3.00 to $r.oo, the same as 

 of non-resident members. The President explained that tliis 

 does not affect the customary election fee of $5.00. Program : 

 "The Gypsum Deposits of New York," by Mr. A. L. Parsons, 

 being a preliminary report of his original studies under the 

 Director of the N. Y. State Museum, illustrated with lantern 

 slides and closing wath an historical sketch of the process of 

 manufacturing g3^psum, 



AVm. -A. Bryan of the Bishop Museum, Honolulu, de- 

 scribed this museum with the help of lantern slides. He then 

 •described his present work here in Pillsbur}- Hall, where he 



