434 BOTANICAL GAZETTE [JUNE 
it was found desirable to conduct the experiments in the wind for 
only a fraction of the time that they were conducted in still air; 
but afterward, for comparison, all readings were computed on the 
basis of quantity lost per hour, and finally on the basis of 1%™ lost 
by the naked blotter per hour. When all the above requirements 
had been discovered and complied with, a great many readings were 
obtained in each series, all'agreeing within the limits of experimental 
fluctuation. All the experiments were conducted in the laboratory 
in February, March, and early April, and therefore in an artificially 
heated very dry room. The fan was run very rapidly in all cases. 
In the following tables the first and fourth columns represent the 
average quantity in grams lost by each blotter per hour in all the 
later readings taken. The second and fifth columns show the same 
quantities reduced to the basis of 12™ for the naked blotter. The 
retarding effect in the third and sixth columns was obtained by 
subtracting the loss under cloth, hair, cotton, or wax from the 
quantity (1£™) lost by the naked blotter. By “increase in efficiency 
in the seventh column is meant the number of times greater the 
retarded effect in wind was compared with the same in still air. The 
last column represents the number of times this increase in efficiency 
in wind was greater than the increase in efficiency of wax. 
Series I.—Coverings used: (a) one layer of very thin linen cloth, (b) two layers 
of the same cloth, (c) wax coating. 
STILL AIR Wind 
Gm Ratio to Retard- re) Ratio to Retard- | Increase Times 
per hour| 7 84 | i . per hous Bel et ing, gm eff. wax 
pore blotter... 1.0. 268 | ¥.000 f+... 2. 4.036 | 000-1 3s | eee 
r layer cloth... .| 0.358 | 0.899 | 0.101 | 2.670 | 0.634 | 0.365 | 3-6 os 
2 tapers cloth... | 0.338 | 0.849 | o.151 | 2.110 | 0.501 | 0.497 | 3-3+ .< 
Wert Se 0.181 | 0.455 | 0.545 | 0.780 | 0.185 | 0.815 | 1-5 i 
Series II.—Coverings: (a) one layer thin linen cloth covered with very thin 
layer of cotton, texture of linen easily seen through the cotton, (b) one layer of linen 
and one layer of thick cotton batting about 2¢™ thick, (c) wax. 
Naked pow dei | 0.308 1 900 1... < z, 1,000 | 64. aK 
Thin cotton..... 0.262 | 0.864 | 0.136 | 1.430 | 0.432 | 0-568 ay 
Thick cotton. 0.219 | 0.722 | 0.278 | 0.870 | 0.263 0.737 2165 
Wat.) 32s. 0.153 | 0.505 | 0.495 | 0.740 | 0.223 | 9.777 | 1-55 
