General Notices. 281 



first, a certain proportion of water in the grains; and, secondly, that the air 

 surrounding them be in an extremely moist state. 



In air thus charged with moisture the grain commences by absorbing 

 water; and, when it has absorbed a sufficient quantity, if the temperature is 

 constant, the air, still saturated with vapour, keeps the external membrane in 

 a state of humidity favourable to vegetation. If the humidity of the air varies, 

 then the external membrane is not humid enough to perform its functions. 



Messrs. Edwards and Colin have studied, according to these principles, the 

 effect of the different kinds of humid soil on germination ; and, finally, they 

 have determined the effects of air saturated with vapour on vegetation, and 

 have arrived at the result, that this is the condition of the air the most favour- 

 able for almost all plants. 



In confirmation of this view, they have cited the observations made at 

 Havanna by M. De la Sagra, and the practice in the stoves in England ; where, 

 by saturating the air with vapour, pme-apples are obtained of the weight of 

 81b. {UE'cho du Monde Savant, April 12. 1837.) 



Connexion between Meteorology and Vegetation. — " M. Boussingault has 

 addressed a note to the Academie des Sciences of Paris, which is entitled 

 ' Comparative Examination of the Meteorological Circumstances under which 

 our common Grains (the Cerealia), Turkey Wheat (Maize), and Potatoes, 

 vegetate at the Equator, and in the Temperate Zone.' In this examination, 

 the author has first made investigations into the time which elapses between 

 the first springing of the |)lant and its full maturity. He then determined 

 the temperature of the space of time which separates these two extreme epochs 

 of vegetable life. By comparing these data concerning any given plant which 

 is cultivated both in Europe and America, he arrives at this curious result : 

 that the number of days that separate the commencement of vegetation from 

 its maturity is more consideral/le in proportion as the mean temperature under 

 the influence of which the plant grows is less ; the duration of the vegetation 

 will be equal, however different the climate may be, if this temperature is 

 identical in the two places ; and it will be shorter or longer, according as the 

 mean heat of the period of time necessary for the accom[)lishment of the 

 vegetation is itself greater or less ; in other words, the duration of the vege- 

 tation appears to be in the inverse ratio of the mean temperatures. So that, 

 if you multiply the number of days during which any given plant vegetates in 

 these distant climates by the mean temperature of the actual period of its 

 vegetation, you will obtain numbers which are very nearly equal. This result 

 is not only remarkable, insomuch as it seems to indicate that, under all climates, 

 the same annual plant receives, in the course of its existence, an equal quantity 

 of heat; but it leads also to a direct practical result, in enabling us to decide 

 upon the possibility of introducing any particular vegetable into a country, as 

 soon as we know the mean temperature of the months there." {Fldl. Journ., 

 vol. xxii. p.383., 1837.) 



Ki/anismg Wood for Garden Purposes, — In Vol. XI. p. 536., a short notice 

 is given of the nature of Mr. Kyan's process for the preservation, not only of 

 every kind of wood, but also of every kind of vegetable fibre, whether in the 

 form of cloth or cordage. The object of Mr. Kyan's composition is, to effect 

 for wood what tanning effects for leather ; and the chemical rationale of both 

 processes will be found given in the Architectural Magazine, vol. ii. p. 236. 

 During the last twelvemonths, we have heard various accounts of the success 

 of Mr. Kyan's invention ; and the general effect upon our minds, till lately, 

 has been rather unfavourable towards its use than otherwise. Mr. D. Beaton, 

 however, informs us, that, while at Haffield (which place he has just left : see 

 p. 205.), he had an opportunity of using it and seeing it used ; and that he has 

 formed a very favourable opinion, at least as to the use which might be made 

 of it in gardening. He has liad several deal boards saturated with it, and 

 tallies for naming plants cut out of them ; and he has seen thin elm boards, 

 which, after being newly sawn up, had been saturated with the composition, 

 remain in the sun, against a wall with a southern exposure, a whole summer. 



