i2d 



The mean proportion of advance which the wind makes 

 with the sun's course on the East side of the compass, as re- 

 sults from the foregoing table, is nearly twice as much as such 

 advance is on the West side, for the mean proportion of the 

 advance on the East side is 2*28, whilst on the West side it 

 is only 1'2L And it seems to show that the progi'ess of the 

 wind round the compass in the direction of the sun's course 

 is retarded chiefly by westerly winds. 



I may also state that the horizontal movement of the air 

 has a maximum at a point similar to the maximum of wind 

 frequency and wind oscillation, for on reducing and refer- 

 ring the horizontal movement of the air for 1869 to the four 

 cardinal points, I find the mean values to be as follows : — 



Cardinal points N E S "W 



Mean horizontal move- ) ._ __ --w --l, 



mentoftheair ... j ^1 99 117 117 



Thus the maximum lies between the South and the West. 



" On Black Bulb Solar Radiation Thermometers exposed 

 in Various Media," by G. Y. Vernok, F.RA.S., F.M.S. 



Being desirous to make some comparisons of the readings 

 of black bulb thermometers exposed in various media, I got 

 Messrs. Negretti and Zambra to make me a set of three 

 thermometers, in addition to the ordinary black bulb maxi- 

 mum in vacuo. 



The glass tubes containing the thermometers were filled 

 with hydrogen gas, carbonic acid gas, and atmospheric air, 

 at 82° F. ; the latter thermometer being described in the 

 tables as filled with compressed air. The instruments were 

 all alike, the glass tube enclosing them being of equal thick- 

 ness. The thermometers were all compared with the 

 Greenwich standard, and require no index error coiTection. 



The observations were made in the years 1861 to 1865, 

 and the period embraced was just four years. Since the 

 latter year the observations have been discontinued, but the 

 thermometers remain in the same position they were 

 originally placed in. 



