VOL. XXV.] PHILOSOPHICAL TRANSACTIONS. 357 



leather, their diameter was 3 inches and a half. A mercurial gauge was also 

 included. To the upper hemisphere was screwed a large brass wire, which 

 past through a box of leathers screwed on the upper plate, and could easily be 

 moved up and down without suffering any air to pass with it. To the upper 

 part of this slip-wire was screwed a cock, through which the air was to be 

 injected. In this manner the lower and upper plate were screwed strongly to 

 the receiver; into which, after an atmosphere of air had been thrown, (which 

 was easily discoverable by the gauge, the air in it possessing but half the space 

 it did before,) the syringe was taken off, and an iron with an eye was screwed 

 on in its place, by which the whole apparatus was suspended on a triangle. 

 Then into the scale, which hung at its bottom, was put so much weight as, 

 with its aggregate, amounted to full ]40 pounds,* before the hemispheres 

 could be parted: the friction of the slip-wire through the box of leathers was 

 very inconsiderable. 



I afterwards repeated the same experiment with the like success. And to try 

 how it would answer in every way, I exhausted the same two hemispheres of 

 their air, and then found that the like weight was required for their separation, 

 as when the additional atmosphere of air was thrown on their outer sur- 

 faces, without withdrawing the included. And further to confirm the same, 

 I not only exhausted the inner air from the hemispheres, but after that including 

 them within the receiver, I likewise injected the san>e quantity of air on their 

 outer surfaces, as in the former experiment, and then found that 280 pounds 

 (which was double the weight before required) did not separate them. I was 

 unwilling to add more (though I knew a small addition must have done it) 

 fearing the breaking some of the weaker parts, which I thought were in danger 

 by the fall of such a weight: the experiment being apparent and satisfactory 

 without it. 



Some Natural Observations in the Parishes of Kinardsey and Donington in 

 Shropshire. By the Rev. Mr. George Plaxton. N° 310, p. 2418. 

 November 6, 16/3, I was inducted into the parsonage of Kinnardsey, where 

 I was incumbent upwards of 30 years; at my induction I found a great many; 

 aged people in the parish, and taking the number of the inhabitants I found 

 that every sixth soul was Qo years of age, and upwards; some were 85, and 



* This experiment yields a pressure of the atmosphere of about 1 4| pounds averdupoJs> on . 

 each square inch, not of the convex surface of the hemisphere, but of the flat area of its plane 

 section, or great circle. And it shows that in such pressures, the effect is to be estimated from the 

 flat section, and not from the convex or outer surfece. 



