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I 



XLII. Oji Co7itempora7ieoiis Meteorological Observations, as 

 proposed by the Royal Society of Edinbiirgh. By Thomas 

 SguiRE, Esq. 



To the Editors of the Philosophical Magazi?ie and Annals of 

 Philosophy. 



Gentlemen. 



HEREWITH send you a Meteorological Table contain- 



ino- the monthly means of the barometer, thermometer, 

 &c. as obtained from daily observations made at 8 A.M. at 

 Eppino-, during the year 1826, and also the depth of rain for 

 each month of the last five years. I have also added another 

 table of the hourly observations made at this place on the 1 7th 

 July, 1826, agreeably to the vv'ish of the Royal Society of 

 Edinburo-h. In this latter table I have moreover given the 

 computed altitudes of my barometer at Epping above that of 

 Mr. Bevan's at Leighton-Buzzard ; the mean of which agrees 

 so well with that obtained from similar observations made at 

 the two places in 1821, as given in the 58th vol. of the Philo- 

 sophical Magazine, from the computations of Mr. Bevan, jun., 

 that for this reason I was induced to trouble you with ihem 

 on the present occasion. 



It may not be improper to say something respecting the 

 instruments used in these observations, as relates to their con- 

 struction and locality, — particulars which ought not to be lost 

 sif^ht of, as a knowledge of such viimiti(E are sometimes of 

 great importance, especially when any deductions are intend- 

 ed to be made from such observations. 



First, The barometer is a portable one, of superior work- 

 manship ; it has a capacious cistern and a large tube, but there 

 is no adjustment for the change of level in the mercury of the 

 cistern, neither is the neutral point nor the ratio of the tube 

 to the cistern marked upon it. These are certainly imperfec- 

 tions ; but as the diameter of the cistern is very great com- 

 pared with that of the column of mercury, and as the point of 

 zero is, most probably, between 29 and 30, no great errors 

 could have arisen from these causes, in the hourly observa- 

 tions, under the then atmospheric pressure. This barometer 

 with its attached thermometer hang in an open situation, with 

 the surface of the mercury in the basin 12 feet from the ground, 

 free from the rays of the sun, and from the effects of artificial 

 heat- 



The external thermometer is freely exposed to the air in 

 the shade, with a N.W. aspect ; the bulb is perfectly bare, 

 and it is so situated as not to be affected by direct radiation : 

 — its heisrhl from the ground is about 5 feet. 



The 



