212 OK THE UTILITY OF THE NATURAL SCIENCES. 



Even purely descriptive botany may be usefully applied to agri- 

 culture. Certain plants, which are injurious to cattle, will be eaten by 

 tbem when pasture is deficient ; and some noxious plants will be eaten 

 when dry and mingled with bay, which animals reject in the green 

 state. A knowledge ot descriptive botany would enable the farmer to 

 remove these, as well as profitless weeds, and thus improve Ids grounds 

 for the advantage of his stock. The wild flora of a country or district 

 affords a valuable indication of the nature of tbe soil and its subsoil. 

 Thus, the heath on elevations indicates a dry soil ; the fern, that it is 

 deep as well as dry. The deer-hair (Scirpus ccespitosus) grows commonly 

 over bogs, resting on clay. In the lower situations, the broom 

 (Spartium scoparium) tenants the deep light gravels. The whin, the 

 coarser gravels upon clay subsoil. The rush (Juncus conglomeraius,) 

 tells the intelligent farmer that good land is rendered useless for want 

 of drainage. The common sprit (Juncus articulatus), that the land is 

 not fertile. Sweet gale [Myrica Gale), that it is still worse. The rag- 

 weed (Senecio jacobcea), in arable land, betrays an ill-cultivated loam. 

 The marsh marigold (Caltha palustris), or the wild water-cress, in 

 water meadows, tells the owner that the land is fully irrigated. The 

 common rattle (Rldnanthus christi), that the meadow is exhausted. The 

 pry (Carex dioica) that water is stagnating beneath its surface ; and 

 these are only a few of the truths which wild flowers teach the intelligent 

 cultivator. Botanists have, indeed, long been at work for the farmer — 

 a fact no one will be willing to dispute who remembers that the sloe, the 

 blackberry, and the crab, are nearly all the fruits indigenous to England ; 

 and that hardly a grass, a flower, or a vegetable, that is now cultivated, 

 is a native of the island. 



It is to the study of botany we are indebted for a knowledge of 

 certain vegetable growths which are destructive to timber. "Mr. 

 Schweinitz had in his collection fine specimens of the Dematiurn aluta, 

 taken out of the ships of war built by our government on Lake Erie, 

 where, in a few years, he remarks, ' this little fungulous enemy com- 

 pletely destroyed that fleet which had so signally vanquished the arma- 

 ment of Britain.' " 



Linnaeus, by his botanical knowledge, detected the cause of a 

 dreadful disease among the horned cattle of the north of Lapland, 

 which had previously been thought equally unaccountable and irre- 

 mediable. 



A large portion of the materials employed in civil and naval archi- 

 tecture, and many of our most valuable medicines, are derived from 

 the vegetable kingdom. It is estimated that at this time there are 

 about 85,000 species of plants which have been distinctly characterised. 

 For the means of distinguishing them from each other, and, conse- 

 quently, for the ability to recognise, amidst the host, those adapted to 

 the purposes for which we seek them, we are indebted to the labors of 

 botanists. 



