Date: 1858
To those persons who took an interest in the science of aeron autics, Lapwing's conversation never failed to be highly instructive and entertaining.  Were they already learned about the matter, he would discourse to them on the specific gravi ties of atmospheric gases ; explain, by the theory of dynamics, what velocity a balloon would gain from unobstructed acceleration, how their buoyancy was affected by the weight of apparatus , and how the fluid she contained was affected by oscUlating motions, and the like.  He would show how resistance was in creased by the diameter of the air-vessel, and could prove by algebra that in the descent of parachutes, if A denoted the circumference of the parachute and of the total weight of the machine, the velocity of descent might be expressed in round numbers by 3f y /.