410 BOTANICAL GAZETTE [JUNE 
TABLE IV.—Continued. 
Cloth bulb Cotton bulb Time ° Difference Time difference 
61°F. 68°F. 355 sec. or (3,90) 155 Bec. 
61 68 370 6 aS 155 
61 66 380 5 Ce 155 
60 65 405 , aia 5 145 
9 64 425 5 2a7 160 
58 63 445 5 2.7 185 
7 65.5 475 5-5 (2.7 210 
56 61 510 5 2.7) 270 
6 60 550 4 2.1 310 
5 59 585 4 2.1) 545 
4 8 630 4 2.1) 545 
4 57 685 3 1.5) 545 
3 7 745 4 2.1) 1083 
3 6 780 a £25 1083 
3 5 895 2 eae. 1083 
2 55 IOI5 a (i.5 1300 
2 54 1175 2 (1.0 1300 
I aie 2155 a a | 480 
49 -! 2635 2 (126 1440 
49 50 3355 EG s§ 
48 49 40°75 Se Ne 
As expected, the retarding effect was apparent in this rather 
violent experiment, but it was not great. The maximum degree 
difference of 10° was less than one-half that produced by the bud- 
scales in Table III, while the time difference through the greater 
part of the experiment ranged from o to 4 minutes. I think it may 
be inferred that the wool in the horsechestnut bud retards the pene- 
tration of heat, when the changes are at all great, by 0.5—3 minutes. 
At any rate it seems evident to me that the retarding power of the 
wool in such buds as horsechestnut is insufficient to explain the 
presence of such a structure. This appears not only from experi- 
ment but from a general consideration of the thinness of such struc- 
tures compared with the relatively great temperature differences 
which they are supposed to offer protection against, and must in 
order to be effective. Their true function, it seems to me, lies in 
an entirely different direction, as we shall see somewhat later. 
In concluding this study of the relation of bud-scales to temper- 
ature the following summary may be made: : 
Bud-scales or bark cannot “keep out cold” during the cold 
spells of winter. ; 
They seem not to modify the temperature sufficiently to be of 
