My 
- 102 British Association for the Advancement of Science. 
laminz, were reflected at the hinder surface, and came out again 
after refraction at the first. Now it is obvious that the necessary 
conditions of acceleration and retardation of the rays could be 
thus obtained ; and the vast multitude of exceedingly thin lamine 
_ which are produced in the plate of mica, by the process of Prof. 
Forbes, far surpassed any thing which, by the most delicate me- 
chanical operations we can hope to obtain. These researches are 
also of the utmost importance as tending to throw light on the 
internal structure of metals. Young, with his usual sagacity long 
since conjectured, from the well known fact that-very thin leaves 
of gold transmit greenish light with almost unimpaired regularity, 
that the surfaces of all metallic plates consist of very thin lam- 
ine, pervious to light, and that the phenomena of their polari- 
zing influences depended on this. Fresnel followed out this con- 
ception, and traced mathematically the mode in which the polar- 
ization would take place. The present researches not only con- 
firm these views, which were heretofore only conjectural, but 
actually show, how under certain conditions, elliptic and circular 
polarization could be obtained by a method similar to that produ- 
cing ordinary polarization. 
Mr. J. F. Goddard described an apparatus which he had con- 
structed, by means of which he could exhibit in the Oxyhydrogen 
microscope, all the beautiful phenomena of polarized light. 
Mr. Addison presented tables of meteorological observations 
made at Great Malvern, in Worcestershire, from 1835 to 1838 
inclusive. From these tables it appears, that the mean tempera 
ture of Malvern is 47.79; the mean barometrical pressure 1s 
29.386 in., and the mean dew point at 9 A. M., is 43.79. The 
range of temperature during the four years, is from 9° on the 
20th of January, 1838, to 84° on the 5th of July, 1836. The 
range of the barometer is from 28.010 in., November 29, 1838, to 
30.228, October 14, 1837. 
Mr. Julius Jeffreys offered a few observations on the meteorol- 
ogy of elevated regions. In 1824 he traversed through a space 
of 200 miles the higher range of mountains in the protected 
States in the Himalayas, for the purpose of conducting inquiries 
into the meteorology of those regions, and the character of the 
climate in a medical point of view. His observations were mi 
during six months, upon mountain heights and in their subjacent 
valleys, from an elevation of 16,300 feet down to 4,000; and of 
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