470 ON USEFUL AND BOOK I. 



the box and holly ; the last and heel maker the alder and birch. 

 Iron-founders use charcoal of any kind. Gunpowder-makers 

 use that of the dogwood, sallow, alder, and hazel. Turpentine 

 and its oil are extracted from the larch and the silver fir. Resin, 

 tar, pitch, and lamp-black, from the spruce and the pine tribe. 

 Potash may be extracted from any wood, but principally from 

 the beech, ash, and elm. Wine may be made of the sap of 

 some trees, as the birch ; sugar of the sap of others, as the 

 sugar-maple, &c. 



21; The relative value of timber depends almost entirely upon 

 local circumstances. Oak and elm proper for ship-building, 

 growing in the neighbourhood of a dry-dock, will be" more va- 

 luable than if it were a hundred miles up the country. Under- 

 growth of dogwood, sallow, and alder, in the neighbourhood of 

 a gunpowder manufactory, is of great value : but, at a distance, 

 it can be used only as fuel, &c. There are, however, some 

 kinds of wood that, from their universal application, are valu- 

 able everywhere ; such as the oak, the elm, the ash, the beech, 

 and to which may be added, as the most valuable, the larch. 

 There are other kinds which, from their scarcity, are valuable 

 everywhere, as the box, the holly, and the yew. The lighter 

 products, such as birdlime, potash, turpentine, pitch, &c. 

 may be reckoned equally valuable everywhere. The tree that 

 would be most valuable in a particular situation, may not there 



