Miscellaneous Intelligence. 

 iices of some of the papers read before the v 



ing the exact height, for 

 It was argued on the 

 ujpoiuesis ot the atomic constitution of bodies, that the upward resuHant 

 of the molecular forces on any atom, since it decreases as the height in- 

 creases, must eventually become just equal to the force of gravity, and 

 that beyond the height at which this equality is satisfied, there can be no 

 more atoms, the atmosphere terminating with a small finite density. It 

 has been generally stated that the earth's atmosphere is about 45 miles 

 high, but on no definite grounds, and the estimates of the height have 

 been very various. Against the opinion that it extends as far as the moon, 

 It was argued, that, as the moon would in that case attach to itself a con- 

 siderable portion by its gravitation, which would necessarily have some 

 connection with the rest, there would be a continual drag on the portion 

 more immediately surrounding the earth, and intermediately on the earth 

 Itself, which would in some degree retard the rotation on its axis. Hence, 

 if, as there is reason to suppose, the rotation be strictly uniform, the earth's 

 atmosphere cannot extend to the moon. The author also stated that if 

 by balloon ascents the barometer and thermometer were observed at two 

 heights ascertained by observation, one considerably above the other, and 

 both above the region in which the currents from the equator influence 

 the temperature, data would be furnished by which an approximate de- 

 termination of the height of the atmosphere might be attempted. 



On the Augmentation of the Apparent Diameter of a body hy its 

 Atmospheric Refraction; by the Rev. Prof. Challis.— For reasons given 

 in the preceding communication, it was assumed that atmospheres gener- 

 ally have definite boundaries at which their densities have small bat finite 

 values. Two cases of refraction were considered : in the one, the curva- 

 ture of the course of a ray through the atmosphere was assumed to be 

 always less than that of the glJbe it surrounds ; and in the other, the 

 curvature of the globe might be the greater. The former is known to be 

 the case of the earth's atmosphere ; and it was supposed that, afortiort, 

 this must be the case with respect to any atmosphere the moon may be 

 supposed to have. On this supposition it was shown that the apparent 

 diameter of the moon, as ascertained by measurement, would be greater 

 than that inferred from the observation of an occultation of a star, be- 

 cause, by reason of the refraction of the atmosphere, the star would dis- 

 appear and reappear when the line of vision was within the moon's appa- 

 rent boundary. The same result would be obtained from a solar eclipse. 

 It was stated that, by actual comparisons of the two kinds of determina- 

 tions, such an excess to the amount of from 6" to 8" was found. This 

 difference may reasonably be attributed to the existence of a lunar atmo- 

 sphere of very small magnitude and density. The author also stated that 

 trora this result there would be reason to expect, in a solar eclipse, that a 

 slender band of the sun's disk immediately contiffuous to the moon's 

 border would be somewhat brighter than the othtr parts, and advised 



