254 



CASSELL'S POPULAR GARDEN IXG. 



Crab, Gloria Mundi, Hambledon Deux Ans,- Hoary 

 Morning, London Pippin, Lord Derby, Norfolk 

 Bearer, Golden Reinette, Nonsucli, Royal Russet, 

 Small's Admirable, Striped Beaufin, Tower of Glam- 

 mis, Waltham Abbey Seedling, Wormsly Pippin, 

 Winter Majetin, Rymer. 



Apples for Warm Localities.— i)mrr^. — 

 Devonshire Quarrenden, American ' Mother Apple, 

 Cox's Golden Drop, Cornish Aromatic, Golden 

 Reinette, Margil, Melon Apple, Pitmaston Non- 

 pareil, Ribston Pippin, Ashmead's Kernel, Claygate 

 Pearmain, Cornish Gilliflower, Court Rendu Plat, 

 D'Arcy Spice, Lamb Abbey Pearmain, Golden 

 Harvey, Golden Pippin, Sam Young. Kitchen. — • 

 Lord Suffield, Cellini, Cox's Pomona, Emperor 

 Alexander, Lemon Pippin, Lord Derby, Mere de 

 Menage, Calville Blanche d'Hiver, Waltham Abbey 

 Seedling, Alfriston, Brabant Bellefleur, Lane's 

 Prince Albert, Royal Russet. 



Apples for Cooler Localities and Scot- 

 land. — Dessert. — King of the Pippins, Oslin, Ravel- 

 ston, Red and Yellow Ingestre, Cockle Pippin, 

 Court of Wick, Court Rendu Plat, Golden Reinette, 

 Red Astrachan, White Paradise, Sykehouse's Russet, 

 Nonsuch. Kitchen. — Tower of Glammis, Warner's 

 King, Y'orkshire Greening, Keswick CodHn, Bed- 

 fordshire Eoundling, Brabant Bellefleur, Manks' 

 Codlin, Dutch Codlin, Hawthornden, Rymer, Royal 

 Russet, Nelson Codlin. 



MANUEIISTG IN THEOEY AND 

 PEACTICE. 



By John J. Willi s. 



NITRATES AS PLANT-FOOD.^ 

 i LTHOUGH plants are unable to assimilate the 

 1 \. free nitrogen of the air, experiments demon- 

 strating the fact that nitric acid is capable of per- 

 fectly supplying vegetation with nitrogen have been 

 carried out by Boussingault. 



Two seeds of a dwarf Sunflower {ScUanthus argo- 

 phijllus), were planted in each of three pots, the soil 

 of which, consisting of a mixture of brickdust and 

 sand, was freed from all nitrogenous compounds by 

 ignition and \vashing with distilled water. To the 

 soil of pot A, Fig. 7, nothing was added save the 

 two seeds and distilled water, with which all the 

 plants were watered from time to time. With the 

 soil of pot B were incorporated small quantities of 

 phosphate of lime and bicarbonate of potash, in 

 order that the plants growing in it might have a 

 soluble mineral supply. Finally, the soil of pot c 



received the same mineral manures as pot b, and, in 

 addition, a small quantity of potassium nitrate (salt- 

 petre) . 



The seeds were sown on the 5th of July, and on 

 the 30th of September the plants had attained the 

 relative size and appearance seen in the diagrams, 

 where they are represented in one-eighth of their 

 natural dimensions. 



Nothing can be more striking than the influence 

 of the nitrate on the growth of plants, as exhi- 

 bited in this experiment. The plants a and b ai-c 

 mere dwarfs, although both carrj' small and imper- 

 fectly developed flowers. The plant c, on the con- 

 trary, is scarcely smaller than the same kind of plant 

 would be when grown under the best conditions of 

 garden culture. 



AVe gather from Boussingault's experiments, as 

 from those of Lawes and Gilbert, that without some 

 compound of nitrogen in the soil, however much 

 there may be in the atmosphere, vegetation cannot 

 attain any considerable luxiuiance, notwithstanding- 

 all requisite ash constituents are present in abun- 

 dance. 



The plants supplied with nitrate of potash as- 

 similated sixty-six times as much nitrogen from the 

 manure as was acquired by a and b from external 

 sources. 



The Soil as a Source of Plant-food. — 



The next question to consider is the amount of plant- 

 food contributed naturally by the soil itself in a 

 virgin state. 



We learn by the study of geology that the earth 

 upon which we H^^ has passed through great 

 changes, extending over vast periods of time. 

 All soils have been produced by the disintegration 

 of rocks, which, through the influence of rain, frost, 

 and air, have gradually crumbled to pieces. The 

 diversity of soils greatly depends upon the character 

 of the primitive rock from which they have been 

 derived. Small particles of pulverised rock, b}' the 

 help of living animals and of vegetable growth, 

 have been broken dowTi into continually smaller 

 fragments, and lastly into a dust-hke powder; 

 and this substance, when mixed ^-ith decay- 

 ing animal and vegetable mr.tter, forms a soil 

 capable of growing plants. The elements taken 

 from the soil in its virgin condition were retm-ned 

 to it on the decay of the plants which it had 

 nourished, or on the death of the animals which fed 

 upon the plants produced. 



Each year, as time went on, a certain portion of 

 the vegetable growth died, leaves and branches fell, 

 and portions of the roots decayed, causing the sur- 

 face soil to become rich in carbon and nitrogen. The 

 atmosphere of the soil, which at first differed but 



