858 



POPULAR SCIENCE MONTHLY. 



ash of the old flashing and safety matches 

 has been retained, and the sesquisulphide 

 of phosphorus is used iostead of the white 

 or red phosphorus of the old matches. The 

 latter substance, besides the indispensable 

 qualities of fixity and resistance to atmos- 

 pheric influences, has the two important prop- 

 erties of inflaming at 95° C, much nearer the 

 igniting point of white phosphorus (60° C.) 

 than of red (260° C), and being therefore 

 easier to light; and of having a low latent 

 or specific heat. With these properties em- 

 bodied in the inflammable composition of the 

 head, the new match is expected to be com- 

 paratively free from accidental explosions 

 during manufacture and export, to take fire 

 by friction, and to burn steadily and regu- 

 larly. The expectation has so far been ful- 

 filled. The phosphorus compound has a 

 special odor, in which the sulphur character- 

 istic predominates, but, not boiling under 

 880° C, does not become offensive in the 

 shops ; and the match heads made with it 

 do not emit the phosphorescence which is 

 often exhibited by matches made with white 

 phosphorus. It is only feebly toxic by di- 

 rect absorption, experiments on guinea pigs 

 indicating that it is only about one tenth as 

 much so as white phosphorus. 



Trees as Land Formers. — John Gifford, 

 in a paper presented to the Franklin Institute 

 on Forestry in Relation to Physical Geogra- 

 phy and Engineering, mentions as illustrating 

 the way forests counteract certain destruc- 

 tive forces, the mangrove tree as " the great 

 land former which, supplementing the work 

 of the coral polyp, has added to the warm 

 seashore regions of the globe immense areas 

 of land." The trees grow in salt water sev- 

 eral feet deep, where their labyrinth of roots 

 and branches collect and hold sediment and 

 flotage. Thus the shore line advances. The 

 seeds, germinating on the plant, the plantlets 

 fall into the water, float away till their roots 

 touch the bottom, and there form the nucleus 

 of new islands and life. The forest con- 

 stantly improves the soil, provided the lat- 

 ter is not removed or allowed to burn. The 

 roots of trees penetrate to its deeper layers 

 and absorb great quantities of mineral mat- 

 ters, a large percentage of which goes to the 

 leaves, and is ultimately deposited on the 

 surface. " The surface soil is both enriched 



by these mineral substances and protected 

 by a mulch of humus in varying stages of 

 decomposition. As the lower layers rot, new 

 layers of leaves and twigs are being con- 

 stantly deposited, so that the forest soil, in 

 the course of time, fairly reeks with nourish- 

 ing plant food, which seeps out more or less 

 to enrich neighboring soils." The forest is 

 also a soil former. "Even the most tender 

 rootlet, because of its acidity, is able to dis- 

 solve its way through certain kinds of rock. 

 This, together with the acids formed in the 

 decomposition of humus, is a potent and 

 speedy agent in the production of soil. The 

 roots of many species of trees have no diffi- 

 culty whatever in penetrating limestone and 

 in disintegrating rocks of the granitic series. 

 As the rock crumbles, solid inorganic mate- 

 rials are released, which enrich neighboring 

 soils, especially those of the valleys in regions 

 where the forest is relegated to the mountain 

 sides and top, as should be the case in all 

 mountainous regions. In view of the destruc- 

 tion caused by mankind, it is a consoling 

 fact that Nature, although slowly, is gradu- 

 ally improving her waste lands. If not in- 

 terrupted, the barest rock and the fallowest 

 field, under conditions which may be called 

 unfavorable, will become, in course of time, 

 forest-clad and fertile. The most important 

 function of the forest in relation to the soil, 

 however, is in holding it in place and pro- 

 tecting it from the erosive action of wind 

 and rain." 



The Atlantic Slope.— The Atlantic slope 

 of the United States is described in the New 

 Jersey State Geological Survey's report on 

 the Physical Geography of the State as " a 

 fairly distinct geographical province. Its 

 eastern boundary is the sea ; its western 

 boundary on the north is the divide between 

 the drainage flowing southeast to the sea and 

 that flowing northeast to the St. Lawrence. 

 Farther south its western limit is the divide 

 between the streams flowing east to the At- 

 lantic and those flowing west to the Ohio and 

 Mississippi Rivers." The line between it and 

 the geographical province next west follows 

 the watershed of the Appalachian system of 

 mountains. It is divided, according to ele- 

 vations, into several subprovinces, all of 

 which elongate in a direction roughly paral- 

 lel to the shore. Next to the coast there is 



