506 Mr. J. Glaisher's Remarks on the Weather 



the transversal lines. Strange as may seem M. Ragona's 

 theory, it deserves examination ; but I confess that that of the 

 Venetian Protessor appears to me to be very obscure. To 

 explain the encroachments of the coloured bands in the lon- 

 gitudinal direction, we must admit that the spectrum is double, 

 and that its elements overlap at right angles. The too great 

 brevity of the author, which is limited to the paragraph above 

 quoted, does not allow us to suppose that such is his opinion. 

 Moreover, these lines, fur from constituting a fact opposed to 

 the theory of undulations, are, on the contrary, an interesting 

 confirmation of its truth. 



LXVII. Rema7-ks on the Weather during the Quarter e7iding 

 March 31, IS^S. By James Glaisher, Esq., of the Royal 

 Observatory, Greeu'wich'^^ . 



IN the February Number of your Magazine you did me the 

 favour to insert my remarks upon the weather during the 

 quarter ending December 31, 1847. The weather of the 

 past quarter has been as unusual as that of the preceding, and 

 some account of it may probably interest your readers. 



The quarterly meteorological returns for the past quarter 

 furnished to the Registrar-General have been obtained from 

 thirty-five different places, situated between the longitudes of 

 5° 18' W, and 0° 16' E. ; and between the latitudes of 50° and 

 B5°. These observations have been all rigorously examined 

 and reduced by myself, and their results are worthy the at- 

 tention of meteorologists. The following are the particulars 

 of the weather during the quarter ending March 31, 1848. 



The weather during the past quarter has been remarkable 

 in many respects. The daily temperature of the air has for 

 the most part been above the average, yet there was a period 

 of exceedingly cold weather between the 20th and 28th of 

 January ; the departures from the average on the 26th, 27th, 

 and 28th, were 12°-8, 10°- 8, and 16" respectively. The tem- 

 perature then suddenly increased to 6^*5 above the average 

 on the 30th; and for the most part the daily values after- 

 wards exceeded those of the average, or differed very little 

 from them. 



It may perhaps tend to clearness if I speak of each subject 

 of investigation separate!}'. 



The mean temperature ojthe air at Grecnxmch — 



For the month of January was 34°-6, which is 1^*7 above 

 that of 1842, 4 --5, S"-7, 9^-1, and 0°-5 beloixi those in the 

 years 1842 to 1847 respectively; or it is S°'8 helo'w the ave- 

 rage of these six years. 



* Communicated by the Author. 



