138 LAIN AND PLEASANT TALK 



mineral elements necessary to the tree, and besides, much 

 organized matter received into the plant from the atmos- 

 phere ; soils therefore are gaining instead of losing. If 

 owners of parks or groves, for neatness' sake, or to obtain 

 leaves for other purposes, gather the annual harvest of 

 leaves, they will, in time, take away great quantities of mine- 

 ral matter, by which the soil, ultimately, will be impover- 

 ished, unless it is restored by manures. 



Leaf-manure has alw\ays been held in high esteem by gar- 

 deners. But many regard it as a purely vegetable sub- 

 stance / whereas, it is the best mineral manure that can be 

 applied to the soil. "What are called vegetable loams (not 

 peat soils, made up principally of decomposed roots), con- 

 tain large quantities of earthy matter, being mineral-vege- 

 table, rather than vegetable soils. 



Every gardener should know, that the best manure for 

 any plant is the decomposed leaves and substance of its own 

 species. This fact will suggest the proper course with refer- 

 ence to the leaves, tops, vines, haulm, and other vegetable 

 refuse of the garden. 



The other fact connected with the leaf, is its function of 

 Exhalation. The greatest proportion of crude sap which 

 ascends the trunk, upon reaching the leaf, is given forth 

 again to the atmosphere, by means of a particularly beauti- 

 ful economy. The quantity/ of moisture produced by a 

 plant is hardly dreamed of by those who have not specially 

 informed themselves. The experiments of Hales have been 

 often quoted. A sun-flow^er, three and a half feet high, 

 presenting a surface of 5.616 square inches exposed to the 

 sun, was found to perspire at the rate of twenty to thirty 

 ounces avoirdupois every twelve hours, or seventeen times 

 more than a man. A vine ^vith twelve square feet exhaled at 

 the rate of five or six ounces a day. A seedling apple-tree, 

 with twelve square feet of foliage, lost nine ounces a day.* 



* Lindley's Horticulture, p. 42-44. Grey's Botany, p. 181. 



