VOL. I.] PHILOSOPHICAL TRANSACTIONS. 77 



And, when the same author alleges that it must be known, when a light 

 body reascends from the bottom of the water to the top, in what proportion 

 of time and swiftness it rises, he seems not to have considered, that in this 

 experiment, the times of the descent and ascent are both taken, and computed 

 together; so that, for this purpose, there needs not that nicety which he 

 mentions. 



Also, whereas it is further excepted, that this way of sounding depths is no 

 new invention ; the answer is ready, that neither is it pretended to be so, in 

 the often quoted tract ; it being only intimated there, that the manner of per- 

 forming it, as it is in that place represented and described, is new. 



A New Statical Baroscope. By Mr. Boyle. N" 14, p. 231. 



I caused to be blown, at the flame of a lamp, some glass bubbles, as large, 

 thin, and light, as I could then procure, and choosing among them one about 

 the size of a large orange, and weighing one dram ten grains, I counterpoised 

 it in a pair of scales, that would lose their equilibrium with about the 30th 

 part of a grain, and were suspended in a frame. I placed both the balance and 

 the frame by a good baroscope, from whence I might learn the present weight 

 of the atmosphere. Though the scales were not able to show me all the va- 

 riations of the air's weight that appeared in the mercurial baroscope, yet they 

 did what I expected, by showing me variations so small as altered the height 

 of quicksilver half a quarter of an inch, and perhaps much smaller than those : 

 nor did I doubt, that if I had nicer scales I should have discerned much smaller 

 alterations of the weight of the air, since I had the pleasure to see the bubble 

 sometimes in equilibrium with the counterpoise ; and sometimes, when the at - 

 mosphere was high, preponderate so manifestly, that the scales being gently 

 touched, the cock would play altogether on that side at which the bubble was 

 hung; and at other times, when the air was heavier, that which was at the first 

 but the counterpoise only would preponderate, and, upon the motion of the 

 balance, make the cock vibrate altogether on its side. And this would conti- 

 nue sometimes many days together, if the air so long retained the same weight; 

 and then, upon any change of weight, the bubble would regain an equilibrium, 

 or a preponderance, so that I had oftentimes the satisfaction, by looking first 

 upon the statical baroscope, to foretel whether in the mercurial baroscope the 

 mercury were high or low. 



So that, the matter of fact having been made out by variety of repeated ob- 

 servations, and by sometimes comparing several of those new baroscopes toge- 

 ther, I shall add some of these notes about this instrument, which readily occur 

 to my memory, reserving the rest till another opportunity. 



