306
THEORY AND PRACTICE
TRACT 37..
The Gun.
Charge of Powder.
Velocityof flame,
length
wt.
Values of
b
oz.
a
h
P
n
V
4
3-45
2-54
2-25
1700
3841
i
28-53
8
5-99
5-08
4-38
1821
3464 -
16
11-07
10-16
8-66
2075
2896
4
3*45
2-54
2-25
1720
4127
2
38 43
8
5-99
5-08
4"38
2015
3976
16
11-07
10-16
8-66
2068
3305
4
3-45
2-54
2-25
1784
4544
3
57-70
8
5-99
5-08
4-38
2241
4629
16
11-07
10-16
8-66
2264
3995
4
3-45
2-54
2-25
1776
4791
4
80-23
8
5'99
5-08
4-38
2282
4999
16
11-07
10-16
8-66
2300
4405
Then, by computing the velocity for every one of the twelvecases, by the last formula, they come out as they are arrangedin the last column of this table. And here it is seen that thesenumbers, for the velocity of the elastic flame, gradually in-crease from the shortest gun, to the longest, from the num-ber 3000 to 5000, as might be expected to happen from thedifferent lengths of the guns, but in a far smaller degree,like the numbers for the value of n, in the last column butone. The four mediums, among the three numbers for eachgun, are 34-00, and 3803, and 4389, and 4732 ; also the me-dium among all these is 4081. But, by an experiment of adifferent kind, Mr. Robins found the velocity of the flamecome out as high as 7000, which is probably nearer thetruth, as we suspected, before making the computation, forthe reasons before mentioned, and chiefly by taking so muchas half the weight of the charge for the value of p, while itis more likely that it should not be more than iorjso muchas has been assumed for p. If a calculation be made with j.of the same value of p, the result comes out between 7 andS thousand, which may probably be nearer the true quantity j