EXPERIMENTS ON HYDRANGEA HORTENSIS. 27 



colours might have proceeded from distinct plants closely inserted in 

 the same pot or ground. This variation from rose to blue, and vice 

 versa, I think oilers one, and only one, probable solution, viz., that 

 some property or colouring matter in the soil had, for an indefinite 

 period, remained insoluble, or in that state in which the roots of the 

 plants could not assimilate or absorb it. But to return to the instance 

 of the flowers losing their blue colour, and returning to their ordinary 

 rose colour; — may it not be inferred that the chemical agent favour- 

 able to the production of the former may have been exhausted in one 

 instance, and in other instances, by removal to other localities, be 

 lost, or, more correctly, neutralized by its active properties being 

 brought into contact with others of a counteractive agency? May 

 not even the application of water, as a medium through which other 

 agencies operate, account for the occasional sudden disappearance or 

 presence of colour ? 



The power of one essential element may be perfectly neutralized, 

 until it is operated upon by its affinity with a second. 



It is known that the Hydrangea is successfully cultivated in Bel- 

 gium with flowers of a rich deep blue ; but in some instances are 

 singularly inconstant, varying in colour with alternate seasons, even 

 the native soil, when removed to a distance, seldom producing the 

 same effect. 



Experiments have also been tried in various forms by applying the 

 ferruginous waters of Passy, but without effecting the least difference. 



Should I be favoured with any additional evidence, as the result of 

 further experiments, I shall have much pleasure in communicating 

 the same to your interesting and valuable publication ; at the same 

 time, I should feel gratified and instructed if other subscribers to your 

 pages, in common with myself, would also give any information they 

 may possess upon the same subject. There are few instances, if any, 

 in the cultivation of plants so novel and beautiful as the effect and 

 contrast produced by the blue-flowered Hydrangea ; nor shall I easily 

 forget, if ever, the pleasing astonishment and gratification I expe- 

 rienced in first beholding it, producing as it did, by its magnificent 

 corymbs of fine blue floral envelopes, one of the most pleasing varie- 

 ties of shade upon which the eye can repose ; and its value perma- 

 nently enhanced by its long continuation in bloom, nobly fitted as a 

 medium to convey the mind " from nature up to nature's God," by 



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