SECRETARY'S REPORT. gg 



high a price with us, yet increase of productiveness and o^ profit 

 is 'perfectly sure here. Some advocates of draining, indeed, go 

 so far as to assert that all lands are benefited by it. With 

 such we have no controversy ; merely remarking that it will be 

 in ample season to discuss the merits of draining such as over- 

 lie a porous subsoil, when those which unquestionably need it 

 have received due attention. 



A safe test to decide whether it be urgently necessary or not, 

 may be thus applied: dig a hole three feet deep; if at anytime, 

 water is found to remain in it for three days continuously, 

 whether from rains or from the contiguous soil, there can be no 

 question whatever. Such lands are familiarly spoken of as 

 cold, and very properly so ; but what makes them cold ? not 

 certainly because more water falls on them than on others, or 

 because the water which does fall is any colder. It is because 

 that which falls is retained until euaporated, instead of passing 

 away downwards. Evaporation produces cold. If a person 

 after bathing, stands in a current of air, he feels the cold thus 

 caused. Water, in passing into the state of vavor, absorbs 

 heat, and in this case, it takes the heat from the wet body, and 

 so its warmth is sensibly lessened. 



Water, in being evaporated from the soil, absorbs heat from 

 it, and so the soil becomes colder. If we apply heat to water 

 it passes off as vapor, and no more heat is carried off by vapor, 

 when we heat the water over a fire, and thus bring it to a state 

 of vapor, than when it evaporates more sloAvly from the soil. 

 Now calculate how many gallons of water must be evaporated 

 from an acre of land which rests upon a hard pan, a solid clay 

 or other retentive subsoil, before vegetation can go on success- 

 fully, and ascertain how many degrees of heat every gallon 

 must abstract from the soil in the process ; and we shall have 

 some data by which to judge how much heat could be saved to 

 that acre, if ive could only tap it in such a way as to draw off^ 

 the water from the bottom, in liquid form, instead of having it 

 pass away from the top as vapor. 



Thus we see that draining such lands, necessarily renders 

 them warmer, by saving heat. It may not be easy to say exactly 

 how much warmth is thus realized ; but it is believed to be. 

 equivalent to a remove of several degrees of latitude south- 



