VOL. XXIV.J PHILOSOPHICAL TRANSACTIONS. 1*22? 



The Observations made with this new Baroscope are as follow. -•~'\. While the 

 mercury of the common baroscope is often known to be stationary 24 hours 

 together, the bubble of the new baroscope is rarely found to stand still one 

 minute. 2. Suppose the air's gravity increasing, and accordingly the bubble 

 ascending; during the time that it ascends 20 inches, it will have many short 

 descents of the quantity of 4- inch, 1, 2, 3, or more inches, each of which 

 being over it will ascend again : these retrocessions are frequent, and of all 

 varieties in quantity and duration, so that there is no judging of the general 

 course of the bubble by bare inspection, though you see it moving, but by 

 waiting a little time. 3. A small blast of wind will make the bubble descend; 

 a blast that cannot be heard in a chamber of the town, will sensibly force the 

 bubble dawnward. The blasts of wind sensible abroad cause many of the 

 abovesaid retrocessions, or accelerations, in the general course; as I found by 

 carrying my baroscope to a place where the wind was perceptible. 4. Clouds 

 make the bubble descend. A small cloud approaching to the zenith effects 

 more than a great cloud near the horizon. In cloudy weather, the bubble de- 

 scending, a break of the clouds, or clear place, approaching to the zenith, has 

 made the bubble to ascend; and after that break had passed beyond the zenith 

 a considerable space, the bubble again descended. 5. All clouds, except one, 

 hitherto observed by me, have made the bubble to descend. But the other day 

 the wind being north, and the course of the bubble descending, I saw to the 

 windward a large thick cloud near the horizon, and the bubble still descended y 

 but as this cloud drew near the zenith, it turned the way of the bubble, making 

 it to ascend, and the bubble continued ascending till the cloud was all passed, 

 after which it resumed its former descent. It was a cloud that yielded a cold' 

 shower of small haiL 



Concerning some Fossils. By Mr. Edward Lhwyd, Keeper of the Ashmolean 

 Repository in Oxford. N° 29], p. 1566. 

 The state of fossils is quite different in Essex, from what it is in Wales and 

 Ireland. In these latter, the shells are generally crystalline; but in Essex,, and 

 sometimes about Oxford, they are testaceous; which difference is doubtless to' 

 be attributed to the soil, and particularly to the chalk and flint of Essex, which 

 those other countries want, excepting a small part got in the north part of Ire- 

 land, But there it is remarkable that their chalk is absolutely petrified; I mean,, 

 whereas the flints are in England embodied in chalk, they are there in a chalk- 

 white lime stone. And as chalky countries alone afford those echinitae, which' 

 I have stiled pileatus, galeatus, and cordatus; so I could never find them in 

 all my travels except at that place; from whence in the time of paganism the^ 



b2 



