ACTION OF THE SALTS OF IRON ON VEGETATION. 



471 



of the leaves, exert a specific action on the 

 coloring matter of the diseased or altered 

 leaves of plants, denominated chlorotic ; 

 that they restore the natural color of these 

 organs, and thus contribute to re-establish 

 the health of the plant, a result which is ob- 

 tained quite independently of a union of 

 these acids with other bases, as lime or so- 

 da ; and that, in this respect, waterings and 

 sprinklings of suitable solutions of these 

 salts can be very usefully employed in hor- 

 ticulture, and also for general cultivation 

 on vegetation subject to this form of dis- 

 ease, such as vines, pears and other fruit 

 trees. 



" 2. That these salts, although their ac- 

 tion is not as prompt and as apparent on the 

 plant in its natural healthy state, appear in 

 many cases to operate beneficially on its 

 growth ; that different circumstances, con- 

 sisting chiefly in the nature of the soil and 

 the plant, particularly merit the specific at- 

 tention of agriculturists ; and that new ex- 

 periments are necessary to determine to 

 what extent the salts may be available in 

 agriculture, although the use of pyritous 

 ashes, already employed in many localities, 

 offers a favorable indication for the employ- 

 ment of sulphate of iron under other cir- 

 cumstances. 



" The extended labors of M. Gris on 

 this subject, the numerous experiments to 

 which he has devoted himself to prove the 

 facts we have collected, the knowledge of 

 which he has given proof, and the perseve- 

 rance with which, for many years, he pur- 

 sued a result which seemed to him impor- 

 tant, and which he has in reality attained, 

 appear to us to merit in a high degree the 

 encouragement of the Society, and w^e pro- 

 pose, as the most flattering evidence of its 

 esteem for his labors, to place him on the 

 list of candidates for the title of Corres- 

 ponding Member." 



Adolphe Brogniakt, 

 Membre de V Academic des Sciences. 



M. Gris has since addressed the folloAV- 

 ing note to the Royal Horticultural Society 

 of Paris, which we find in their Annales : 



" Allow me to beg my colleagues, and 

 horticulturists generally, who wish to re- 

 peat my experiments, to operate with the 



precautions and in the doses given in my 

 notices previously published. The Society 

 will understand that I cannot be responsible 

 for any success or failure growing out of ap- 

 plications too weak, or too strong, when the 

 temperature is too low, upon glaucous foli- 

 age that sheds washes ordinarily applied, 

 etc.; this would be the subject of intermi- 

 nable discussions. 



" In all experiments, carefully made, like 

 those in the royal garden, I distinctly state 

 that ninety-five cases in every hundred 

 have been successful. This year not a sin- 

 gle leaf has been blackened or discolored 

 by the application of the salts of iron, in the 

 long series of experiments to which I have 

 devoted myself in this establishment. 



" In the mean time the following are 

 about the proportions to which it is neces- 

 sary to adhere. 3 to 4 drams of sulphate 

 of iron {green copperas) to a quart of w^ater, 

 for all applications to be made by watering 

 the roots. 



" One-fourth of a dram, only, (2 gram- 

 mes, seulment,) to a quart of water, for show- 

 ering or bathing the surface of the leaves. 

 (The copperas should be dissolved just be- 

 fore applying the solution.) 



" With one ounce of common copperas, 

 (sulphate of iron,) we may therefore prepare 

 16 quarts of the solution, fit for all usual 

 applications to the leaves of plants. 

 I have the honor to be, &c., 



EusEBE Gris." 



Eebiarks by THE Editor. — We are in- 

 clined to look upon the discovery of M. Gris 

 as detailed in the foregoing report as one of 

 the most important made in horticultural 

 science for many years past. 



Every experienced cultivator well knows 

 how little science has hitherto ofl^ered as re- 

 medies for any constitutional or organic dis- 

 eases of plants. To prune, to improve the 

 soil by manures, to renew it by deeper til- 

 lage, to exterminate injurious insects — this 

 is nearly the extent of the remedial agents 

 in common use. 



In the mean time there are various mal- 

 adies, like ihe yellmos in the peach tree, and 



