IN THE CONSTRUCTION OF SHIPS IN THE ROYAL NAVY. 43 



tor abounds, and is propagated vigorously in the New Forest 

 and other parts of Hampshire, in Norfolk, and the northern 

 counties, and about London ; and there is but too much rea- 

 son to believe that the numerous complaints that were heard 

 about our ships being infested with what was called, impro- 

 perly enough, dry-rot, were owing to the introduction of this 

 species of oak into the naval dock-yards, where, we under- 

 stand," observes a writer in the Quarterly Review, " the distinc- 

 tion was not even suspected." Here again a scientific know- 

 ledge of the subjects connected with the profession of the 

 planters, and other parties concerned in this supply of spurious 

 oak to our shipwrights, would have prevented the mischief. 

 The science of Botany teaches that the Quercus sessiliflora 

 may be distinguished from the Quercus Robur, the true Na- 

 val Oak, by the following characters: "The acorn stalks of 

 the Robur are long, and its leaves short ; whereas the Sessili- 

 Jlora has the acorn stalks short, and the leaves long : the acorns 

 of the former grow singly, or seldom two on the same foot- 

 stalk ; those of the latter in clusters of two or three, close to 

 the stem of the branch *." 



A striking train of instances in which the importance of 

 Entomological knowledge is displayed of that science, the 

 study of which has of late years furnished results so import- 

 ant in the progress of Natural History, may be shown in the 

 history of those insects, which, in their larva or grub state, 

 attack and destroy the trees of the forest. To employ, with 

 some slight modification, the language of a distinguished En- 

 tomologist, whose attention, some years since, was officially 

 called to the subject by Government, so little attention has 

 hitherto been paid to the causes of disease in trees, that few 

 persons ever think of attributing it to any other origin than 

 one entirely vegetable, or, in other words, to the constitution 

 of the plants themselves. Yet in every case, perhaps, in which 

 the disease is infectious, and particularly where it is confined, in 

 a plantation or forest, to the individuals of one species of tree, 

 as to the Elms, or to the Oaks, we may pronounce with cer- 

 tainty that it proceeds from the attacks of some insect. Every 

 species of tree, nay indeed every species of plant, seems to 

 have one or more species of insect destined by nature to feed 



* It is proper to observe that I make these statements, so far as the use 

 of the timber of the Quercus sessilijlora in the Royal Navy is concerned, en- 



*^ Quercus Robur is figured 



ny, vol. xix. tab. 1342 ; and the Qu. sessiliflora, in vol. xxvi. tab. 1845, of the 

 same work. 



