Z6 THE PROPERTIES

which had the bore cylindrical, and the vent situated at thebottom, were constructed according to the proportions laiddown in the First Book of Artillery.

Nature of Guns. Length of Bore. Weight.

Pounders.

Calibres.

Ctfii,

?•

Ib.

4

— 27

— 9

1

9

8

— 27

— 18

2

10

16

— 23

— ZI

3

26

32

— 20

— 57

2

17

They were fired on their carriages, and loaded with theladle : the powder was the common-grained cannon pow-der; four strokes of the rammer were given to the wad overthe powder, and three to that over the shot, by the famegunner, and as nearly as possible with the fame force. Thewads were of twisted hay, properly gauged ; the shot wereweighed, to fee that they were exactly equal in weight; andthe windage was in the ratio of twenty to twenty-one.

The guns being loaded, and pointed along the range, werefired with the axis always horizontal; which was ascertainedby the pendulum and water-level. After each discharge, thelength of the recoil was measured; the wheels were placed inthe fame position, between lines, to prevent the slightest dif-ference. The coins placed under the breech were marked be-fore the discharge; and if moved by the Ihock, the expe-riment was not considered as exact.

These precautions being taken, the smallest charges wereused at first, and increased gradually till the ranges beganto diminish: three rounds, at least, were fired with eachcharge. The charge that gave the longest range having beenascertained by repeated firings, the principal object was, duringthe last five days, to remark what alteration might arise fromany changain the state of the atmosphere ; with this view, thefame gun was fired each afternoon, with the charges markedin the following table. For example, from the four-pounderthree rounds were fired, with each of the charges of i Ib, 4 oz.i Ib. 10 oz. 2 Ib. 1 oz. of powder ; the following day, fromthe eight-pounder three rounds were fired, with the chargesof 2 Ib. 7 oz. 3 Ib. 50Z. and 41b. 2 oz. of powder. Inlike manner the sixteen-pounder was fired on the third, andthe thirty-two-pounder on the fourth day. At length, toform a comparison of the ranges of the different guns, on thefifth day the four and eight-pounders were fired, with charges