370 Scientific Intelligence — Botany. 



mmv destructive about the villages of Saintes, Tonnay-Charente, 

 and Rochefort. Roofs and floors are often completely riddled in 

 these villages by these animals so feeble in appearance ; and even 

 entire houses have been so destroyed in their foundations, that 

 they had to be abandoned or rebuilt. The danger from these de- 

 predations is the greater, that they work altogether out of sight, 

 and respect with extreme care the surface of the bodies they at- 

 tack. The archives of Rochelle for certain years have been com- 

 pletely devoured by the termites (excepting the outer surface, 

 which leaves no evidence of the destruction within), and of recent 

 years they have been inclosed in zinc. At La Rochelle the inva- 

 sion has even extended to the arsenal and the prefecture, and the 

 whole village is threatened. 



M. de Quatrefages has made some experiments which solve 

 the problem of their destruction. He has shewn that the gases 

 which are most energetic are chlorine and nitrous vapour, N0 4 ; 

 sulphurous acid is less active, and oxide of nitrogen, N0 2 , acts 

 only when it can be transformed into hyponitric acid, under the in- 

 fluence of a little oxygen. The gases have been made to act on 

 fragments of wood infested with the termites, and have so pene- 

 trated into the deeper termitic cellules that none have escaped. 



As the application of gas in many cases must be inconvenient, 

 it is recommended to prepare the wood before employing it in con- 

 struction. The method hitherto employed for preserving woods 

 have had reference rather to protection against decay than insects. 

 There is an exception in the process of Bethell, which consists in 

 saturating the wood with a bituminous oil rich in naphthaline, a 

 material proceeding from the distillation of the bitumen of coal. 

 The cross timbers of the Stockton and Darlington Railway, pre- 

 pared in this way ten years since, are still untouched ; and the 

 same is true of the timbers of part of the London and North- 

 western Railway. At the port of Lowestoft, the naphthalized 

 tiles are wholly exempt from the attacks of insects, while wood 

 unprepared is more or less deeply eaten. The disastrous results 

 mentioned by M. de Quatrefages will not fail to call attention to 

 this process, which has been sometimes objected to on account of 

 its making the wood more combustible. — (American Journal of 

 Science and Arts, vol. xvi., No. 46, p. 107, 2d Series.) 



BOTANY. 



17. Experimental Researches on Vegetation; by M. George 

 Ville. Communicated by the Earl of Rosse, P.R.S. — After stat- 

 ing that it has often been asked if air, and especially azote, 

 contributes to the nutrition of plants ; and, as regards the latter, 

 that this question has always been answered negatively, the author 

 remarks, it is however known that plants do not draw all their 



