180 Prof. J. Brocklesby on the Influence of Color on Dew. 
different Eeohonss of flannel, shreds of the same material, texture, 
and color, until t weights were equalized ; and before every ex- 
periment this ile was taken, the same shreds as far as pos- 
= being always employed. By so doing uniformity in weight 
as attained, without increasing the extent,of exposed surface ; 
ee what was due to the thickness of the shreds. And the 
effect of this is rendered led aioe since it is obvious that its 
slight influence in increasing the amount <3 beat is checked, and 
probably annihilated by two oithing cau 
For the shred being raised by its Ae ase above the surface 
of the larger eee pare shelters the contiguous threads of the 
latter, and thus in a very minute degree arrests their radiation, 
and diminishes their quantity of deposited moisture. Still fur- 
ther, as the thickness of the flannel is doubléd where the shreds 
are plac there here exists, comparing stidtt Shots with those not 
ver outs the quantity of matter*under ‘very ‘nearly the 
same exp urface : a circumstance whichs would eee the 
timination erate, and the contractiorof dew. I th 
fore judge that these antagonist influences may be regarded i in 
their effects as neutralizing each other, and that no ‘sens 
crease or diminution, in the amount of dew contractéd). ¢ 
4 , a 
sult from the superposition of the shreds as above detailed: ss 
thus obtained a uniformity in material weight, effective su 
fibre, and with the exception of a very small variation, in tex : 
for I ‘attribute the variations in the weight of the several colored 
pieces to the greater density of some of the threads in one flannel, 
compared with those of another. The only known difference 
then existing was color. 
The. place of ae was a plot of closely shorn turf in the 
midst of a garden, removed from trees and buildings. In six out 
of the eleven expuinen, detailed in table A, the flannels were 
placed upon the turf itself, and in the remaining five upon a 
smooth board, elevated upon blocks of wood, six or seven inches 
above the turf. In every case the pieces were arranged side by 
side, without any regard to color in their collocation, and the in- 
vestigation was conducted mostly on tranquil nights ; so that the 
variations in the deposition of moisture, arising from a body bein 
aced to the windward or leeward of another, were thereby 
avoided, 
Table of Averages. 
ee Fain in Do. in ao first)Do. in the se-|Do. in the last)Do. - id last, 
LL experiments.| fon [eed Sour, four. i thee: 
rs. rs. grs. ‘ 
White, Sro7 Ei 39- ‘abas | | Obes 
Yellow, 38-73 47°25 38:25 29:75 98: 
ed, 37:27 46- 37:25 27:50 25° 
Green, 37-09 44-37 37 29-12 27-50 
Black, 86:14 43-25 36°62 27-75 26° 
Blue, 25:17 
