SECTION IIL 



397 



of growing trees in New York, found that from November to April, 

 when the bulb of a thermometer was put into a hole made in a trees, 

 the mercury rose higher than in the open air ; and that the colder 

 the weather, the greater of course w^as this difference. From April 

 to November, on the other hand, the thermometer showed a lower 

 temperature in the tree than in the open air. And Ingenhoutz found, 

 that a piece of green paper, hung on a tree, in a warm summer 

 day, felt sensibly warmer than the leaves. Hunter likewise, who 

 was fond of trees, used to keep thermometers in them for months 

 together, and obtained similar results. — The subject is curious, and 

 is the more deserving of the planter's investigation, that the state 

 of the bark, and its power, when thick and indurated, to protect the 

 sap-vessels, are so intimately connected with all facts that tend to illus- 

 trate the subject. 



Note V. Page 66. 



Of the close analogy which subsists between the animal and vegetable 

 kingdoms, many other examples respecting the former might be adduced 

 besides those mentioned in the text, in order to show how universally 

 nature generates provisions for individuals, in order to fit them for the 

 situations in which they are placed. The general rule seems to be, as 

 mentioned in the text, that where there is a great external application 

 of cold, an adequate non-conducting covering is supplied, to prevent the 

 subtraction of internal caloric ; and in the same way, that covering is 

 withdrawn on a greater application of heat. Of the latter the coach 

 or racehorse furnishes a familiar example, with his smooth and silky 

 coat, enjoying the warmth and shelter of a well-constructed stable, 

 when we compare it with the rough and shaggy one which he wears, 

 when running out in winter. The coats of warm-blooded animals ap- 

 pear to be thick and fine, in proportion to the intensity of the cold they 

 are destined to endure ; and they are always thicker and finer in winter 

 than in summer. Accordingly, (as stated in the text,) the fur-bearing 

 animals all inhabit high latitudes, and the value of their skins increases 

 in proportion to the severity of the cold in which they are killed. 



Of the natural clothing of animals in cold countries, the Musk Ox of 

 Melville Island, as observed by late voyagers, furnishes a striking in- 

 stance ; as the immense mass of non-»conducting matter which covers 

 that animal, renders him capable of existing in a temperature where 

 even mercury freezes, and of which we can form no adequate conception. 

 The long, hairy, and dense garb of the Kamtschatka Mammoth, that 

 most powerful of quadrupeds, embalmed in ice, sufficiently proves the 



