AIR DRAINAGE AS AFFECTING ACCLIMATIZATION. 33 



famil}-, but the old owner of the land used to say that he would go up 

 there and he would think that perhaps there would be a bushel of peaches 

 on that tree and he would pick them and find ten bushels on one peach 

 tree. I do not think it was the soil. I think it was simply the situation 

 that caused the whole result. 



Mr. MtDison — Just one word in order that the example I propose 

 may not be misconstrued. The slope of the Gulf from the north side 

 extends through several miles very gradually up and down over small 

 hills and valleys, and on the southern side likewise, so that the killing 

 occurred entirely over the territory north for several miles, while for 

 several miles each side of the river, we had abundant peach orchards. 

 This could not be explained by the southern exposure of hillsides, and 

 must be accounted for by some other theory, and the only theory that 

 they could possibly think of was the slope to the southern side, and the 

 heat in the valley that gradually drifted southward in that case. Now, 

 as to drainage, the idea has been advanced that the drainage about a 

 mountain comes from the top down the side of a mountain. I am in- 

 clined to take issue with that view. The flow is not steadily downward 

 next to the earth from a mountain. It is upward. There is a high swift 

 current of air passing over the top of a mountain. If you will observe 

 over any ridge over which the wind flows in snow-time, the wind blows 

 over the top, and you will find a counter-current coming up and you 

 will find a hollow place. The current comes over it and hits the ground 

 beyond and banks the snow up and there will be a hollow behind it. 

 So it is with the circulation about a mountain ; the air passes over it, the 

 warm air from below comes up the opposite side of the mountain, and 

 that cold air takes its place beyond, and you will find that the freezing 

 is heaviest and begins first in the centre of the valley on a still night. 

 This wedge of cold air from above settles down, and the warm air fol- 

 lows the hillside and flows upward. You build a fire somewhere near 

 a large tree, and you will find that the flames, instead of going up, will 

 seek the side of a tree and will go up the tree, and so the hill has the 

 same power of furnishing a sort of back for the air to creep up while the 

 cold currents drop beyond. 



Mr. Macoun — I think that Mr. }»Iunson is confusing two things, the 

 movement of winds and the gravity falling of cold air. When we speak 

 of air drainage, and the inversion of temperature, we consider the air 

 resting on a plane as absolutely still. Therefore, what he says about 

 air currents across the top of mountains has nothing to do with it. When 

 air gets cooler it drops, and if you cool it on the top of a mountain, it of 

 course, flows down the slopes. In my work on the Rocky Mountains, I had 

 always found that if there are any mosquitos, it is advantageous to camp 

 in one of these cold-air spots, as it drives the mosquitos away, and so 

 our camp is always at the mouth of a caiion, leading up to a mountain, 

 knowing it will not be salubrious for the mosquitos. This matter of in- 

 version of temperature is a matter that has been studied by thermometers 



