tract 34.

GUNNERY.

31

88. Wednesday, August 31, 1785.

Employed tliis day in making part of the survey by theside of the river, for forming the map, and fixing the sta-tions proper for the parties of observers to occupy, inwatching the fall of the balls in the river; and for otherpurposes.

We weighed and measured the pendulum, which hadbeen prepared in a very complete manner, and with strongerbands than before. It weighed just 795 lb. And, by a meanof several times balancing and vibrating, we found 78yinches to be the distance of the centre of gravity below theaxis, and 40-07 the number of oscillations per minute.

After executing part of the survey by the side of theriver, we fired a few balls upon the water, from the Con-victs’or Proof Wharf, to try whereabouts they would fall, andthereby to judge of the proper places for the observersto be stationed at. The gun was n° 2, with 8 ounces ofpowder, and was tried at different elevations. When thegun was elevated at 45 degrees, the balls ranged much toofar, going beyond the stretch of the river, and falling onthe coast of Essex below the point b. But at 15 degreeselevation, the balls ranged to a very convenient distance,namely, a little more than a mile. And their fall in thewater could be very well seen from the side of the rivernearly opposite the place of the fall, and sometimes fromthe gun itself.

On this occasion I took out with me, and employed thefirst class of Gentlemen Cadets belonging to the RoyalMilitar}^ Academy , namely, Messieurs Bartlett, llowley,I)e Butts, Bryce, Wm. Fenwick, Pilkington, Edridge, andWatkins, who have gone through the science of fluxions,and have applied it to several important considerations innatural philosophy. Those gentlemen I have voluntarilypffered and undertaken to introduce to the practice of these