March, 1907.] Difussion of Hydrocyanic Acid Gas. loi 



. The material for this paper was collected in a lagoon near 



San Antonio de los Banos, Havana Province, Cuba. Herbarium 



specimens have been deposited in the herbarium of the New 



York Botanical Garden. 



EsTACiON Central Agronomica, 

 Santiago de las Vegas, Cuba. 



EXPLANATION OF FIGURES OF PLATE VIII. 



Fig. 1. Functional megaspore. 

 Fig. 2. Two-nucleate embryo-sac. 



Fig. 3. Antipodal end of sac in which the antipodals have disap- 

 peared; end. — endosperm. Same age as embryo in Fig. 17. 

 Figs. 4 to 16. Series of embryos. 

 Fig. 17. Outline of embryo same age as Fig. 3. 



EXPERIMENTS TO TEST THE DIFFUSION OF HYDRO- 

 CYANIC ACID GAS IN FUMIGATING HOUSES.* 



A. F. Burgess. 



In February, 1906, a set of fumigation experiments was 

 started to test the diffusion of h3'dro-cyanic gas in fumigating 

 houses, with the object of determining the rapidity with wdiich 

 this gas diffuses, both in empty houses or boxes and also when 

 they are filled with stock, as would be the case when thev are in 

 use. For this purpose permission was secured from the Agri- 

 cultural Department of the Ohio State University to use a 

 greenhouse in which soil experiments are conducted, and the 

 fumigating box belonging to the Horticultural Department of 

 the same institution was also furnished for the tests. 



B_v placing the box on a truck which run on a track it could 

 be pushed outside the greenhouse. In this way it was thor- 

 oughly aired without allowing the fumes to escape in the house 

 and an opportunity was afforded to try several tests out of doors 

 where the temperature was near the freezing point. 



Description of Box: The box was lined with galvanized iron 

 and was 4 ft. x 2>^ ft. x 10 ft. inside measure, making a capacity 

 of 100 cubic feet. 



The cover was hinged at one end and was opened bv using a 

 rope and pulley at the other end. It shut on strips of "felt, and, 

 as the galvanized iron made the cover rather heavy, it would 

 close very tightly without additional weights. Clamps were 

 used, however, in order to make the box perfectly gas tight. 



The generating jar was placed near the end at which the cover 

 was raised, and, in order that no gas might escape while it was 

 being closed, the cyanide was enclosed in tissue paper and 

 dropped by a string through a small hole directly above the jar. 



* Read before the meeting of the Ohio State Academy of Science. 



