144 Professor Leslie^s Remarks cm the Instruments 



twenty-four hours, since the accumulated warmth is counted 

 only once, while the freshness, partaking of the night, is re- 

 peated twice. It would come nearer the truth to assume the 

 middle point between the maximum and minimum, though even 

 this cannot be deemed absolutely correct, because the heat 

 neither mounts nor declines in an uniform progression. The 

 hottest time of the day is generally about two oVlock in the after- 

 noon, and the coldest just before sunrise. The hour of extreme 

 descent is consequently, in most latitudes, very variable ; and it 

 would be difficult to fix the times suited for observing, unless they 

 were more multiplied. But even fewer observations could some- 

 times be made to serve the purpose. In this cUmate, the daily 

 average heat may be reckoned from that of eight o''clock of the 

 morning ; and the month of October is found to have nearly the 

 mean temperature of the whole year. 



The observations usually made with the hygroscopes of 

 Deluc or Saussure, cannot be regarded as affording any definite 

 indication of the dryness of the atmosphere. It would essen- 

 tially contribute to the advancement of meteorological science, 

 if the hygrometer, which I have described, were introduced 

 into general practice. This adoption cannot be very distant *. 



Some of the monks, in the religious houses dispersed over 

 the Continent, might find agreeable and useful occupation in 

 recording the state of the atmosphere. Many of these establish- 

 ments are seated in lofty and romantic situations ; and several 

 of them, destined by their founders for the charitable accommo- 

 dation of travellers, occupy the summits of the most elevated 

 and inaccessible mountains. Accurate registers kept in such 

 towering spots would be peculiarly interesting. 



Meteorological registers might be regularly kept by the junior 

 surgeons in all our medical depots which are scattered over vari- 

 ous points of the globe. Lighthouses, too, would, from their 

 usual position, be well fitted for observing the force and direction 

 of the wind, and the swell and relapse of the tide. The elevation 

 of the water could be most accurately noted by extending a 

 leaden-pipe from the shore into the sea, and bending the nearer 



• We purpose soon to give the results of some interesting observations 

 made with this instrument in the West Indies, and in New South Wales. 



