Miscdlanies. 1 53 



it appears also that nitrate of ammonia, corrosive sublimate, oxa- 

 lic acid, and perhaps oxalate of ammonia, evolve vapor at common 

 temperatures.— /c?em, 



7. On the functions of vegetable lift. — An interesting paper by 

 Gilbert T. Burnett, Esq. containing an account of various exper- 

 iments on the transpiration, absorption, and living functions of vege- 

 tables, is contained in the first number of the Journal of the Royal 

 Institution. The author arrives, in general, at the following results : 



1st. The functions of plants are but relatively distinct : many in- 

 stances occur in which they are intimately blended, and in which, 

 without much care, organs and functions must be, and have been 

 frequently confounded with each other. Organs which have been 

 supposed to be exclusively destined to one function, and incapable of 

 any other, do under certain circumstances perform the functions of 

 other organs. 



2d. Air is essential to the roots of plants; the death of large trees 

 in consequence of embankments around them, (as when raised roads 

 have been made through groves or plantations,) has been ascribed 

 to the accumulation of earth around the trunk, and attempts have 

 been made to obviate the evil by forming cylinders of brick around 

 them, but without effect. Death in these cases is caused by a suffo- 

 cation of the roots. It is well known how favorable the loosening of 

 the soil is to the health of trees, as well as of all other plants. 



3d. Absorption takes place, in most plants, both by their roots and 

 leaves ; the first course of the sap is upward, and its passage (at least 

 frequently) is through the non-spiral tubes. 



4th. The chief current of the sap is axial, for it will traverse the 

 whole extent of the trunk before it will enter any of the branches, 

 how near soever to the root they may be situated, and also when it 

 enters the branches, its course is axial with respect to them. Hence 

 the terminal buds are generally the largest and finest, and the first 

 developed. 



5th. Several leaves of Potamogeton natans, were wiped quite dry, 

 weighed, the end of the petioles covered with soft wax, and after 

 remaining out of water for two hours, they lost from three grains and 

 a half to five and one fourth each. Being put into water, after the 

 lapse of two hours, they were wiped dry and again weighed. They 

 had gained from three to five grains each, which, of course, could 

 have taken place only by absorption through the cuticle. 



Vol. II.— No. 1. 20 



