412 Dr. Barney on the late Solar and Lunar Eclipses, [Dec» 



natrolite and skolezite. At present I rather incline to the latter 

 opinion ; but as it is of much more frequent occurrence than 

 either natrolite or skolezite, mineralogists cannot find any great 

 difficulty to determine the point. I intend, as soon as I have 

 leisure, which will not be till next summer, to examine the 

 different zeolites in my collection, which are pretty numerous, 

 in order to determine to which of these species each of them 

 belong. If any thing should occur during the covirse of that 

 examination worthy of attention, I shall take care to lay it 

 before the public. 



Article II. 



Observations on the late Solar and Lunar Eclipses, and the 

 Planet Venus. By Dr. Burney. 



Eclij)se of the Sun, and its Influence on the Diurnal Temperature, 

 Pressure, and Humidity of the Atmosphere. 



Any increase in the diurnal temperature on the earth must 

 be sensibly felt and considered^ as caused by the radiation from 

 the sun, of whatever substance that luminary maybe composed; 

 and in a solar eclipse like the present, we naturally imagined 

 that a considerable diminution of heat and light would happen, 

 under favourable circumstances, by the interposition of the moon 

 between the sun and the earth. To determhie this experimen- 

 tally, it was found necessary to make previous obsei'vations on 

 the progress of the diurnal temperature, in order to have a stand- 

 ard wherewith to compare the results, and accordingly the 

 preceding day, September ^6, was chosen, being very fair, for 

 that purpose. 



In referring to our notes, we observe that at half-past five, 

 a.m. of that day, the thermometer stood at 51° ; at six, 52° ; at 

 seven, 54°, the sky being then clear, a stratus, or low level 

 cloud on the ground, and a fresh N.E. breeze; by eight o'clock 

 it had risen to 58° ; at nine, to 60° ; at ten, to 64i° ; at eleven, to 

 66-1-° ; at 12, to 67° ; at one, p. m. to 67-1-° ; and at two, to 69° 

 being the maximum for the day : by three, it had sunk to 65-1-°; 

 at four, 64i.° ; at five, 62° ; and at sunset, to 60°. The day and 

 night were fair, and mostly clear, and the lowest temperature in 

 the night was 50°. This being only 2° minus of the lowest tem- 

 perature in the night after the eclipse, and as the medium temper- 

 atures of the two days and nights accord with each other within 

 1-^^°, these preparatory observations may, therefore, be considered 

 a fair standard wherewith to compare the depression of the 

 diurnal temperature during the eclipse. We shall now proceed 

 in detaihng the progress of the temperature of Sept. 7, also 



