METEOROLOGY. 



173 



the boundaries of a science in which, from the want 

 of accurate and uniform registers, there are still so 

 many desiderata. See Arist. De Meteor. Aral. Dios. 

 Ue Luc, Idee* tur la Meteorologie. Forster On Atmo- 

 tpheric Phenomena. Philosophical Transactions, Loud, 

 and EdtM. Leslie On Heat and Moisture. I'lay lair's 

 Outline* of Natural Philosophy. Dalton's Meteorotgy. 

 Wells On Dem. And our articles ATMOSPHERICAL 

 CLOCK, BAROMETER, COLD, EVAPORATION, HYOROMB- 

 TRY, PHYSICAL GEOGRAPHY, PNEUMATICS, TIIERMO- 



MCTKM, &C. ArPKNOIZ. 



While the preceding article was preparing for the 



press, we were carrying on a series of observations with 

 the sympiesometer, suspended in the same apartment 

 with a very delicate mountain barometer It may per- 

 haps be gratifying to some of our readers to see the re- 

 sult of these, at the same time that they will shew on 

 what grounds we formerly ventured to conjecture, that 

 there might be something like absorption between the 

 gas and the oil. Our observations commenced on the 

 4th of September, and were made generally twice a- 

 day, with the most scrupulous attention to accuracy. 

 We shall confine ourselves, however, to the observa. 

 lion at 10 in the morning. 



Meteorolo- 

 gy- 



Compan- 

 son of the 

 sympieto- 

 meier and 

 the moun- 

 tain liaro. 

 meter. 



Compariton of the Sympiexmuter with the Mountain Barometer. 



It appears, from the above table, that the different* 

 the barometer and iyjinniMii, which i al 

 bde, gannrfy ir.rr..,M a* the ton- 

 pentare and prewure mre diminished, though there are 

 alio instances in which this doe* not bold. This fact 

 sufficiently explains what was observed by Lord Gray, 

 and formerly noticed, that the difference between the 

 two instrument*, after progressively increasing for a 

 time, began gradually to diminish ; but it does not ap- 

 pear so eaiy to ex pi Yin the fact itself. It could easily 

 be dbfwu, indeed, from the law which regulate* the 

 1 expansion of permanently elastic fluids, 

 : however accurately the extreme point* of the scale 

 may be determined, if the intermediate space be divid- 

 ed into equal parti, the indications of the instrument 

 caaawt exactly coincide with thoae of the barometer un- 



der all pressures, and at all temperatures ; but whether 

 the error arising from this cause be sufficient to account 

 for the differences in the above table, we shall not at 

 present inquire. We would only remark, that though, 

 in its present state, the sympiesometer cannot perhaps 

 be relied on as an accurate measure of the weight of the 

 atmosphere, its utility aa a marine barometer is unques- 

 tionable. The instrument of this kind most valuable to 

 the navigator, is that which is least affected by the ship's 

 motion, and at the same time most sensible in indicating 

 changes in the pressure of the atmosphere, without any 

 regard to it* absolute weight With respect to the for- 

 mer, the superiority of the sympiesometer is too ob- 

 vious to require being pointed out; and, with regard to 

 delicacy, our own observations would lean us to infer, 

 that it ia also superior to the mercurial barometer. 



