312 STATE rOMOLOGICAL SOCIETY. 



At 4 P. M., Aug. 28, it was 29.47 feet, Temp. 75° Fabrenbeit. 



were also attacbed to tbe stumps of large plants of Indian corn, tobacco, and 

 tbe dablia. Tbe results were not specially different from wbat has been pre- 

 viously observed by Hofmeister and others. The flow continued but a very 

 few days, and tbe pressure varied from eight to twenty-five feet of water. The 

 pressure in all these cases seems to be caused by tbe activity of tbe absorbent 

 tissues of the root; and its cessation results, doubtless, from the stagnation of 

 tiie sap in the gorged cells and vessels, and tbe consequent decay of tbe root- 

 hairs and fibres. 



The frequent displacement of flagging-stones, and tbe damage often done to 

 brick and concrete pavements and stone walls by tbe roots of shade trees, con- 

 sidered in connection with the wonderful expansive power exhibited by the 

 squash in harness, made it evident that growing roots of firm wood must be 

 capable of exerting, under suitable conditions, a tremendous mechanical force. 

 Upon searching the fields for examples of trees standing upon naked rocks, or 

 ridges covered with only a shallow soil, many interesting specimens were readily 

 discovered to demonstrate this fact. 



LIFTING POWER OF HOOTS. 



In South Hadley, Mass., a sugar maple was found which had grown upon a 

 horizontal bed of red sandstone. The tree stood upon the naked rock, over 

 which its roots extended a few feet in three directions into the soil. One root 

 had pushed its way under a slab of rock which measured more than twenty- 

 four cubic feet, and must have weighed about two tons. In tbe course of 

 twenty years or more, this root bad developed to such a size as to raise the 

 elab entirely from tbe bed-rock and from tbe earth, and so that it rested wholly 

 upon the wood. Upon examining tbe tree, it was evident that as it stood upon 

 the horizontal roots which rested on solid rock and bad a diameter of nearly a 

 foot; and as they bad grown by tbe deposition cf an annual layer of wood en- 

 tirely around them; and as tbe heart, now several inches from tbe rock, must 

 once have rested on it; and as tbe rock could not have been depressed, — there- 

 fore, the tree bad been lifted overy year by tbe growing wood of the outside 

 layer. 



Another tree of paper birch having been found growing in a similar manner, 

 one of the horizontal roots was sawed through, and the center of the heart was 

 seen to have been elevated seven inches since tbe tree was a seedling. 



Mr. William F. Flint, a student in the Agricultural College of New Hamp- 

 shire, has rendered valuable assistance in finding specimens of trees which il- 

 lustrate this principle in an admirable manner. 



Now, it; it is clearly dem )nstrated that tbe power of vegetable growth cam 

 lift a tree, and that it must do so, whenever tbe bed of the roots cannot be de- 



