326 Proceedings of the British Association. 



phenomenon, and that the rings were the effect of the double re- 

 fraction of the minute crystals. A few experiments, however, 

 overturned this hypothesis, and I was soon satisfied, by a httle 

 further investigation, that the phenomena arose wholly from the 

 polarization of the transmitted light by refraction, the splendid 

 colors being entirely those of thin plates, which were sometimes 

 arranged so as to have the appearance of concentric rings. The 

 structure by which these effects was produced, was compared by 

 the author to a heap of very deep watch glasses laid one above 

 another. When the thin films were arranged longitudinally, and 

 were inclined to the general surface of the plate, so as to trans- 

 mit the rays obliquely, the light was still polarized, but only in 

 one plane, viz. a plane perpendicular to the plane of incidence. 

 When a drop of water or oil was introduced between the films, 

 the phenomena of polarization as well as of color, instantly dis- 

 appeared. 



Prof. Phillips communicated 7iew experimental researches on 

 rain. He had endeavored, by a new train of researches on the 

 quantities of rain received on horizontal surfaces, at different 

 heights above the ground, and by a contemporaneous series of 

 experiments on the direction and angle of inclination of the de- 

 scending lines of rain drops, and by contemporaneous registration 

 of wind, temperature and moisture, to furnish additional data of 

 importance in the theory of rain. In the second part of his com- 

 munication he described a new rain-gauge, for the purpose of de- 

 termining the direction in which rain comes, and the angle of in- 

 clination at which it descends. For this object, a compound 

 gauge is constructed, having five equal receiving funnels and 

 tubes ; one with a vertical tube and horizontal aperture, the other 

 four with tubes recurved, so as to present the openings of the fun- 

 nels in four vertical planes, directed to four quarters of the ho- 

 rizon. 



Excessive rain. — Prof. Forbes remarked that some doubt had 

 been expressed concerning the remarkable fall of rain at Genoa 

 (not Geneva,) stated in his report of the previous year, viz. 30 

 inches in 24 hours, Oct. 25, 1S22. He now adduced satisfactory 

 proof of its truth. He then noticed some other remarkable falls 

 of rain. Flaugergues, the eminent meteorologist of Viviers, ob- 

 tained, on the 6th of September, 1801, lU Enghsh inches of rain 

 in eighteen hours. On the 20th of May, 1827, there fell at Ge- 



