B. TERRESTRIAL PHYSICS AND METEOROLOGY. 67 



not at present be determined. Only this is clear, that the 

 sun's spots do not directly, through the darkened portion of 

 the sun's disk, act like an eclipse, leaving the remaining 

 portion of the sun's disk to shine upon the earth with undi- 

 minished intensity; for were this the case, since the tempera- 

 ture on the earth's surface is a summation of the total radia- 

 tion from the sun, it would follow that the variation in the 

 temperature would necessarily follow later than its cause 

 that is to say, the minimum temperature on the earth should, 

 to a certain extent, follow the maximum number of sun-spots. 

 The contrary, however, is the case, the number of sun-spots 

 attaining its maximum after the corresponding maximum of 

 temperature in the tropics ; and it appears to the author most 

 likely that the temperature of the sun's surface, from some 

 unknown cause, is highest one or two years before the min- 

 imum of the solar spots. Regarding these spots as compar- 

 atively cold matter slowly melting away on the glowing sur- 

 face of the sun, he remarks that it can not be surprising that 

 the spots should occupy so great a time to completely melt 

 when we consider their immense dimensions. He, however, 

 finds no explanation of the remarkable fact that the retarda- 

 tion of the temperature on the earth's surface, with respect 

 to the sun's spots, is greater near the poles than at the trop- 

 ics, unless it have to do with the phenomena of the moisture 

 in our atmosphere. To this subject, therefore, he proposes to 

 direct attention. In conclusion, as the result of his studies 

 into the appearance of extremely hot and cold years, he states 

 that, according to the data now before him, there is reason to 

 expect a very cold year, in 1875, in Europe. Zeitschrift far 

 Meteorolocjie, November, 1873, 241-265. 



DIURXAL VARIATIONS OF THE WIND AND BAROMETER AT 



BOMBAV. 



C. Chambers, director of the Colaba Observatory at Bom- 

 bay, brings to notice a remarkable relation that has been 

 found to exist between the diurnal variations of the wind 

 and barometer at Bombay. Besides the well-known diurnal 

 variations of the wind, known as the land and sea breezes, 

 the author shows that certain peculiarities of the wind-curve 

 are due to the superposition of a distinct variation, having 

 two maxima and two minima, like the barometer variation ; 



