110 JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



few exceptions — this is not a matter of so much concern, the object not 

 being, as a rule, the production of seed. Still, the requirements of the 

 plant in respect of mineral and nitrogenous constituents are of importance 

 here too, and not only healthy growth, but desired production of leaf or 

 flower, as well as of flavour — as seen in the instances of fruits and vege- 

 tables — are dependent in no small measure on the proper supply of 

 the essential and desirable ingredients through soil or manuring. As 

 mentioned before, each plant needs, however, to be studied for itself, and 

 no definite conclusions can be formed from analysis alone, either of the 

 plant or of its ash constituents. 



I have not unfrequently been asked to say, from the analysis of the 

 ash of a plant — the violet is one I have at present in mind — what the 

 proper manuring for it should be. This is, as I have pointed out, a ques- 

 tion not to be answered from the examination of the ash alone, but has 

 to be taken in conjunction with the soil on which the plant is grown, 

 and the power which that plant has of attacking the various soil 

 ingredients. In short, it has to be the work of experimental inquiry. 



Phosphoric acid is, along with potash, an essential ingredient in 

 seed production, and the pollen of plants is especially rich in phosphoric 

 acid. The development of fruits, vines, hops, &c, would seem to be very 

 dependent also on these two ingredients, and potatoes are much benefited 

 by the use of potash salts. 



Iron, though seldom wanting in ordinary soils, is an esserrial to 

 the production of chlorophyll, and to its influence on the quality of the 

 vine is attributed the excellence of many ferruginous soils. From time 

 to time, indeed, there have come to the front those who have believed 

 greatly in the benefits to be derived from the use of sulphate of iron 

 and other salts of iron, and these latter have not unfrequently been made 

 ingredients of horticultural and garden fertilisers. I cannot say that, 

 for myself, I am satisfied as to the need of salts of iron as special 

 applications ; for iron is one of the most widely distributed constituents 

 of the soil, it is invariably found in the ash of plants, and I do not know 

 of anything to show that it is difficult of assimilation, but the contrary. 



Lime is the next ingredient that calls for attention, and the 

 experience I have had myself strengthens my belief in the great part 

 which lime plays in plant development. While some soils have plenty of 

 it (some, indeed, too much to make good horticultural soils), there are 

 many others in which there is a decided lack of lime, and, speaking 

 generally, I know of few more desirable ameliorations of soil than those 

 that can be effected by the use of lime. Not only does it supply a 

 necessary ingredient of plants, but its action in setting other constituents 

 of the soil free to act as food, and in improving the mechanical and 

 physical conditions of soil, is of the greatest service. Unfortunately, 

 through the increased cost of lime, consequent on fuel being dear and 

 carriage heavy, the " good old practice " of liming land has largely gone 

 out, and I fear that in many cases the soil, deprived of lime by the con- 

 tinual use of artificial manures and forcing top-dressings, has been much 

 impoverished, and can only be properly restored by the use of lime. A 

 soil deprived of lime has a tendency to become " sour " or " acid," and shows 

 this in the prevalence of " finger -and -toe " in root crops, a fungoid disease 



