311 
grasses, especially the pasture grass, has been studied at the Pennsyl- 
vania State College Agricultural Experiment Station, by G. L. Holter 
(Agr. Sci., Vol. III, p. 285), in connection with studies on the 
yield per acre. Samples of grass were cut every few days during the 
season (of 1887), but the comparisons with rainfall and temperature 
showed no definite relation, except, perhaps, that the percentage of 
ash increased as the temperature diminished. The following table 
gives the figures showing the average rainfall and temperature from 
the middle of one period to the middle of the next, and for the average 
of seven plats of ground: 
Yield per acre, Yield per acre, 
Rai Tem- in pounds. Rai Tem- in pounds. 
Period. fall. pera, |= SS Period. fall. Les  ———S—= = 
* | ture. | Fresh| Dry } * | ture. | Fresh! Dry 
grass.| hay. | grass.| hay. 
Inches. of. | lInches.| °F. | 
May 00-2 | oo. a |ewe ee 1,.300| 339 || Aug. 29-Sept.5.| 0.88] 66.5| 147 38 
May 25-June4__| 2.62 61.0 525 130 || Sept. 10-14 ___-.. | 1.58 60.2 | 216 52 
June 6-12_______- 0. 52 b2. 2 325 91 || Sept. 18-21 _.....) 1.50 60.4 202 53 
June 13-22. __.._. 0. 23 70.0 140 41 || Sept. 22-29 ___..-. 0.41 60.2 | 84 24 
June 25-July 2__| 1.75 fioso) 229 65 || Sept. 29-Oct. 2 - .| 0.39 55.9 85 21 
lye Ses see 0.51 67.2 171 60) | |KOctelsali S32 22 | 0.85 45.2 | 32 11 
duly, 13-20) 22. 1.74 67.9 247 | 6% \@cts17=22) 22 2. | 1. 42 46.1 43 16 
July 21-29 ___.._- 0.72 69.2 170 45 || Oct. 30-Nov. 5.- 1.37 45.6 | 9 3 
July 30-Aug.7__| 0.25 75.2 101 34 | ina ee ee __..| 4,977 1,145 
ATi 8-20 Pees £22 1.48 72.6 105 | _ 28 
Aug. 22-28.......| 3.24] 68.6] 145 43 | 
If we assume that the whole season extended from May 10 to Sep- 
tember 29, we may compute the average daily growth, which will be 
found to be very large at first, but rather uniform from June 13 to 
September 16, after which it steadily diminishes. The irregularities 
in the growth from one week to the next have no simple connection 
with rainfall or temperature, but there is no evidence to show that 
other climatic elements, such as sunshine and evaporation, would not 
have thrown some light upon the subject. 
Mr. Holter has also experimented on the yield per acre of pasture 
grass, as measured week by week during the growing season of 
1888 and 1889 at the Pennsylvania State College Agricultural 
Experiment Station. (See Agr. Sci., Vol. V, p. 52.) The plat 
experimented upon represents an average of the uplands of the Alle- 
gheny Mountains. The weather of the season was most favorable 
for the growth of grass, having a heavy, evenly distributed rainfall. 
The following table shows the dates of cutting and the average daily 
growth between these dates, expressed in pounds of dried grass per 
acre. It will be seen that there was a rapid increase in growth up 
to May 21, after which there was a steady decline. The daily 
average for the whole season of one hundred and seventy-eight days 
