166 Transactions of the 



rations, it is no less true tnkt many trees, which have been 

 supposed to be incapable of surviving a northern winter, are 

 now ascertained to be perfectly hardy, and that the power 

 of enduring cold may be increased in others, by a judicious 

 management of soil and situation., , U ^ t)j-;iL-iMV lu 



The phenomenon of vegetable liSfe being destrbyea by 

 cold, probably arises from the vessels, through which the 

 circulation and secretion of the fluids of plants take place, 

 being ruptured by the expansion, from cold, of tlie fluid they 

 contain. In proportion, therefore, to the tenuity of the ves- 

 sels, and the abundance of their fluid, will be the danger to 

 which they are exposed from frost ; and to the strength of the 

 vessels, and the paucity of their fluid, the power of resisting 

 eold. Thus vigorous shoots of the oak, walnut, and many 

 other trees, which are formed with rapidity, imperfectly ma- 

 tured, and highly charged with fluid, are extremely impa- 

 tient of cold, and are even destroyed by a few degrees of 

 frost ; while the twigs and branches of the same trees, which 

 are formed slowly, fully matured, and incompletely flUed 

 with fluid, bear unharmed the utmost rigour of our winters. 

 In acclimatizing, therefore, this law should be carefully 

 remembered, and the situations in which tender plants are 

 stationed, should be those in which their growth is re- 

 strained^ and an excessive absorption of fluid prevented. 



This appears to have been the true secret of the success 

 that has attended the attempts at acchmatizing, which form 

 the subject of Mr. Street's communication. By planting in 

 situations well drained from superfluous moisture, under cir- 

 cumstances where rapid growth was rendered impracticable, 

 and, as we understand, in a garden admirably adapted to 

 the object, from its position, he has succeeded in natura- 

 lizing, in latitude 56° N., plants which have not yet been 

 known to endure the winters even of the parallel of London. 



V. Upon the Culture of Celery. By Thomas Andrew Knight, Esq., 

 F.R.S., President. 



*^ That which can be very easily done, without the exertion 

 of much skill or ingenuity, is," Mr. Knight observes, *' very 

 rarely found to be well done, the excitement to excellence 

 being in such cases necessarily very feeble." This remark 

 is in the present case applied to the cultivation of celery, 

 which, being a native of the sides of wet ditches, might 

 naturally be expected to demand an abundant supply of 

 water when cultivated. Accordingly, Mr. Knight found that 

 by keeping the ground, in which celery was planted, con- 



