| 
| 
| 
| 
| 
MURPHY: RESULTS OF WINDMILL TESTS. OI 
any other 12 foot mill. The results of tests of a 12 foot ‘*Pow- 
er’ mill are shown in Fig. 1. The wheel of this mill is like that of 
mill No. 3. table I. The power was measured with a friction brake 
on a 9% pulley which runs the grinder or other machine. The 
speed of pulley was measured with a Pratt speed indicator, 
D4 
ya & uae Lila ea A a als 3 
Rigi , 
The four curves marked o lbs. 2 lbs. 4 lbs. and 6 lbs. give the re- 
lation between H. P. and wind velocity in miles per hour. Theo 
curve is for no brake load, the brake was off'the pulley The 2 lb. 
curve is for a brake load of 2 lbs; the 4 lb curve for a brake load of 
4 lbs. and the 6 lb. curve for a brake load of 6 Ibs. 
It is easily seen that the power increases with the load above cer- 
tain velocities. At 30 miles per hour the power is nearly propor- 
tional to the load on the mill This fact which accounts for much 
of the difference in the pumping power of windmills has never been 
clearly shown, to the writer’s knowledge. We noticed it in our tests 
made in ’95 and stated the fact in the paper already referred to. (p. 
to4 Vol. 4 Kans. Univ. Quarrerty). This fact is also referred to 
by Mr J. Au Griffiths, Associate Member Institution C. E. in a pa- 
per on ‘Windmills for Raising Water” — published in 1895 in ‘«Pro- 
ceedings of the Institution of Civ. Eng: Voli wrnoe: en Sanaa « \Aln 
