92 REPORT ON THE STATE CABINET. ■ . 



were to take the observation earlier, it would diminisli the subtrahend 

 for the summer ; but the observation for the evening is taken at nine 

 p. M., after cooling has been going on much longer in the winter than in 

 the summer. If, therefore, we were to take the observation earlier in 

 the evening for the winter, it would add something to the minuend 

 for that season ; and thus probably the result would be about as it now 

 stands, if the observation were taken in summer before the heating of 

 the day, and in winter before the cooling for the night had' made any 

 considerable progress. We see that the average difference between the 

 night and the morning temperature for the summer, 2°.89, is nearly 

 double that for the winter, 1°.64. 



The most remarkable phenomenon presented by the above comparison, 

 however, is the great difference between the morning and evening tem- 

 peratures in the month of April, being then o°.42 greater than at any 

 other time in the year. 1 am not of course able to say whether that be 

 a peculiarity of this special locality, or not. During the month of March 

 there are usually more cloudy days than in April, and also much snow 

 and ice to thaw away ; both of which causes would prevent the atmos- 

 phere from liecoming so warm at evening as it would otherwise be. 

 These obstacles being removed, the topmost stratum of the earth's crust 

 would warm fast in April. As, however, the ground is not warm far 

 below the surface, but on the contrary is very cold only a few inches 

 down, it cools very I'apidly during the night. In May the earth becomes 

 warmed to a greater depth. In July the difference between morning 

 and evening temperature is again about as great as in April. This is 

 perhaps to be explained on the ground that the hotter any body, the 

 more rapidly it radiates heat and cools by radiation. 



2. The second phenomenon worthy of comment is the fact that our 

 average for the year is but 47°.20, whereas it ought to be, considering 

 our latitude, about 10° more. I have already hinted at the explanation 

 of this deficiency. It is scarcely 40° of longitude from the northeastern 

 termination of the great old-world mountain range in the promontory of 

 Navarin to the point at which the great North American chain com- 

 mences. From the direction in which these mountain ranges run, it is 

 not probable that they exert much influence upon the winds or the tem- 

 perature in the Pacific ocean. But they approach within about 90° of 

 longitude as between Cape Finisterre, on the Spanish coast, and the high- 

 lands of Texas ; and thus three-fourths of all the polar current is forced 

 to pass through this wind gap of about one-fourth of the earth's circum- 



