Memoirs of the Caledonian Horticultural Society. 327 



the vegetation altogether sickly. Seeds from the same packets, grown on 

 patches of white and of red woollen cloth, were luxuriant and beautiful. . . . 

 The retardation and final suspension of the vegetation are, no doubt, to be 

 ascribed to the iron, the base of the colouring matter in black. 



" Mustard and cress seeds were sown in powdered alum, sulphate of 

 iron, sulphate of soda, sulphate of magnesia, muriate of soda, and muriate 

 of lime, in small glass capsules, and duly watered ; with the exception of 

 the last, which, being a deliquescent salt, did not require it. Two cress 

 seeds only germinated in the powdered alum, but no vegetation appeared 

 in the others. 



" Mustard and cress seeds were partially roasted, by being projected on 

 ignited iron ; yet a great portion of them afterwards grew on wetted flan- 

 nel. Seeds were likewise submitted to the action of boiling water, and 

 the temperature suddenly reduced : all these grew. Hence, some seeds can 

 sustain an elevated temperature without the destruction of their vitality. 



" Peas and beans, with boiling water poured on them, and suffered gra- 

 dually to cool, sprouted in a few hours, and grew remarkably well, having 

 been transferred, when cold, to wetted flannel. This experiment furnishes 

 a very easy method of ascertaining, in a sufficiently prompt way, whether 

 the vegetative power is suspended by age or other causes. 



" I put sprung peas into alcohol, of specific gravity 1812 ; but little pro- 

 gress was made in ten days : those placed in naphtha and ammonia decayed. 

 Peas placed in alcohol, naphtha, and sulphuric ether exhibited no evolu- 

 tion of incipient germination. 



" Mustard and cress seeds were sown in iodine, dilute sulphuric acid, 

 dilute muriatic acid, and dilute nitric acid ; chlorate of potassa, hydriodate 

 of potassa, muriate of iron, sulphate of iron, and caustic potassa : they 

 gave no evidences of germination whatever, though they were regularly 

 supplied with water. 



" Cress sown on carbonate of magnesia, and attentively watered, germi- 

 nated freely : hence there must be some error with the late Mr. Tenant's 

 conclusion, as this experiment is completely opposed to his deductions. It 

 is one of first-rate importance, as many farmers have been induced, from 

 Mr. Tenant's experiment, to discard magnesian limestone, as injurious to 

 vegetation ; though they had a supply of it at hand, and bring from a dis- 

 tance limestone of a different character. 



" Mustard germinated freely in the tincture of iodine, and the vegetation 

 was fine. 



" Tufts of mustard and cress, growing on different parcels of sponge, 

 were placed in capsules with the following solutions : — 



Sulphate of iron (copperas) : vegetation here fell the first victim. 

 Sulphate of copper (blue vitriol) : this fell the second in succession. 

 Acetate of lead (sugar of lead) : this fell the third. 

 Muriate of mercury (corrosive sublimate) was the last survivor. 



" Some younger plants, though nearer the surface, sustained the green 

 colour after the tallest had fallen ; but cress seemed to be the last to suf- 

 fer. The vegetable matter, in each instance, was duly tested by the neces- 

 sary reagents. That with sulphate of iron, after the stems had been 

 macerated with distilled water, became decidedly blue with hydrocyanate 

 of potassa ; that with muriate of mercury was rather equivocal on being 

 examined by caustic potassa. In the specimen destroyed by sulphate of 

 copper, the lower parts of the stems and transverse portions, where they 

 were cut, became of a violet tint with ammonia. The vegetable matter 

 that had been destroyed by acetate of lead, tested with hydriodate of po- 

 tassa, was not appreciable ; but on being crushed in solution of chromate of 

 potassa, the capillary vessels were beautifully dyed by the new-formed 

 chromate of lead. 



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