99tf Questions for Solutlmi relating to Meteorology^ 



sions will be quite sufficient. In the Atlantic, the extremes of 

 these temperatures, as hitherto determined by numerous naviga- 

 tors, are 27° and 29° of the centigrade thermometer (that is 

 80.8° and 84.2° of Fahr.) Taking into account errors in gradua- 

 tion, every one will perceive, that, with a good instrument, the 

 uncertainty of a single observation of the maximum of tempe- 

 rature in the equatorial parts of the Atlantic Ocean, cannot 

 much surpass a degree, and that the constancy of the mean of 

 four distinct determinations may be relied on to a small fraction 

 of a degree. Here, then, is a result easy to be obtained, directly 

 connected with the calorific influences on which the temperature 

 of the earth depends, and as much separated as possible from 

 the effects of local circumstances. It ought to form a meteoro- 

 logical gift, which every age should be anxious to bequeath 

 to that which succeeds it. The officers of the Bonite will cer- 

 tainly not neglect this part of their instructions. The excellent 

 instruments with which they are furnished warrants us to expect 

 all that accuracy and precision which the present state of science 

 demands. 



Of the Calorific Action of the Solar Rays viewed in their 

 relation to the situation of places on the globe. — Animated dis- 

 cussions have taken place among meteorologists regarding the 

 calorific efi^ects which the solar rays may produce by means of 

 absorption in different countries. Some adduce the observations 

 that have been made towards the arctic circle, from which this 

 singular consequence seems to result, that the sun has a more 

 -powerful heat in high thari in low latitudes. Others refuse to 

 admit this result, on the pretence that it is not proved. The 

 observations made at the equator do not appear to them suffi- 

 ciently numerous to be taken as one of the terms of comparison ; 

 and it is thought, besides, that these observations were made un- 

 der unfavourable circumstances. This investigation might there- 

 fore be recommended to the officers of the Bonite. To execute it 

 successfully they would have need of two thermometers, the re- 

 servoirs of which, on the one hand, absorb the solar rays un- 

 equally, and, on the other, are not too sensible to the cool- 

 ing influences of currents of air. This double condition 

 may easily be obtained, if, after having procured two ther» 

 momcters in every respect " alike, the bulb of one of them be 



