Page:Philosophical Transactions - Volume 001.djvu/193

 between 2 and 3 Eights of an Inch difference betwixt them: And having sometimes order'd my servants to take notice of the Disparity, and divers times carefully observ'd it my self, when I pass'd to and fro between Oxford and Stanton, I generally found, that the Oxford Barometer and the other, did, as it were by common consent, rise and fall together so, as that in the former the Mercury was usually ; higher, than in the latter.

Which Observations may teach us, that the Subterraneous steams, which ascend into the Air, or the other Causes of the varying Weight of the Atmosphere, do, many times, and at least in some places, uniformly enough affect the Air to a greater height, than, till I had made this tryall, I durst conclude.

But, as most of the Barometricall observations are subject to exception, so I found the formerly mentioned to be. For (to omit lesser variations) riding one Evening from Oxford to Stanton, and having, before I took horse, look't on the Baroscope in the former of these 2. places, I was somewhat surprised, to find at my comming to the latter, that in places no farther distant, and notwithstanding the shortness of the time (which was but an hour and a half, if so much) the Barometer at Stanton was short of its usual distance from the other, near a quarter of an Inch, though, the weather being fair and calm, there appear'd nothing of manifest change in the Air, to which I could adscribe so great a Variation; and though also, since that time, the Mercury in the two Instruments hath, for the most part, proceeded to rise and fall as before.

And these being the only Observations, I have yet met with, wherein Baroscopes, at some Distance of Place, and Difference of Height, have been compar'd (though I cannot now send you the Reflexions, I have elsewhere made upon them;) as the opportunity I had to make them my self, rendred them not unpleasant to me, so perhaps the Novelty will keep them from being unwelcome to you. And I confess, I have had some flying suspicions, that the odd Phænomena of the Baroscope, which have hitherto more pos'd than instructed us, may in time, if Rh