J»IOVI>G FOnCK. 
165 
/ 
data by which we can determine nearly the pressure by which Cases of diffi- 
the circumference of the wheel is ur^ed. Let p represent 
t that pressure ; then, if the experiments agree with this llieory, moving force. 
1 we should always have p=zi». But we shall look in vain to 
t the results of Mr. Smeaton’s experiments for this equation. I 
• subjciin the comparative values of p and w, calculated from 
I Mr. Smealon’s first table of eight experiments*: 
Experiment 1. p = 2‘3u> 
2. p = 2 3~w 
3. p = 2 I5w 
4. /) = 2-22W 
5. p = 2-I(W 
O', p = 2 \\w 
7- P = 2Q\w 
8 . p = rysu' 
And in the 2/th experiment, p. 1 15, we have p = 2‘7w. 
If these results be correctly stated, Mr. Smeaton might 
truly say, that he found these matters to come out in the ex- 
periments very different from the opinions and calculations of 
authors of the first reputalionf. 
It is true, Mr Smeaton’s maxims agree with some of the 
results brought out by the common theory. His maxims, how- 
ever, are by no means the most important conclusions which he 
has drawn from the results of his experiments; neither can 
I agree with the reviewers in supposing, that he considered 
• If Mr. Sineafon’s reduction of his fifth experiuient, page Hi, be 
couipurcd with the table page 110, it will appear, that he has omitted 
to include in the rpiantitics set down in the table, the weight of the 
scale, pulley, and counterweight. In finding the value of p, I have, 
in each e.xjH'riimnt, taken twice the weight of tiie scale and pulley, 
adder! to tlie counter weight, to be equal to lb. which will be near 
enough for the purpose of comparison. 
It should be observed, also, tliat if the table had been made out in 
the same way, the fourth experiment would have given the maximuui 
elfcct. 
f Phil. Trans, 1776, p. 45'» 
these 
