WITH REFERENCE TO HORTICULTURE. 63 



not effervesce with acids; and sands more than clays." (Agricultural Che- 

 mistry, 6th edit., p. 304.) 



202. In the case of suburban villas, the most important uses of lime are, 

 first, the formation of lime-water for the destruction of insects, snails, 

 worms, &c. ; and secondly, the formation of lime composts to be used as 

 manure. For both these purposes lime must be obtained in its caustic state. 

 In preparing lime-water, a very small quantity of lime in powder will be 

 found to saturate many gallons of water ; and, by letting this settle a few 

 minutes till it becomes clear, the plants or the soil may be watered with it 

 without leaving any coating of lime, which only takes place when the lime 

 is applied in a state of mixture and solution. The causticity of the liquid, 

 owing to the alkali which it contains, lacerates the tender skins of- cater- 

 pillars, earth-worms, snails, and slugs. 



203. Lime compost is formed of caustic lime, at the rate of from sixteen 

 to twenty-four bushels of lime to three times that quantity of earth taken 

 from hedge-banks, cleanings of ditches or ponds, scrapings of roads, or even 

 from the surface of any soil which is somewhat different in its nature or 

 texture from the soil on which the compost is to be laid. Even the sub- 

 stratum of any soil, where good, may be used, and afterwards laid on the 

 surface soil. The compost should lie from nine to twelve months, and be 

 turned over in that time twice or thrice. In every part of Britain this 

 manure may be formed at a moderate expense ; and though it is better 

 adapted for fields than gardens, yet in many cases, and particularly where 

 manure is scarce, it will be found a valuable resource. (See Jackson's Agri- 

 culture, published by Chambers, p. 47.) 



204. Saltpetre, or muriate of potash, when analysed, consists of oxygen, 

 nitrogen, and potassium. Saltpetre is found in almost all plants, and espe- 

 cially those which are cultivated in rich soils. As a manure it sometimes 

 produces extraordinary effects on grass lands and corn crops ; but its action 

 is not understood, and it has been but little used in horticulture. Nitrate 

 of soda produces nearly the same results as saltpetre. From some experi- 

 ments with this salt lately detailed in the Journal of the English Agricultural 

 Society, vol. i. pp. 418 and 423, it appears to have increased the produce 

 of corn crops, but not more so than saltpetre. 



205. Common Salt, or the chloride of sodium, consists of nearly equal parts 

 of chlorine and sodium ; but when dissolved in water a portion of the water 

 is decomposed, its hydrogen unites with the chlorine to form muriatic acid, 

 and its oxygen with the sodium to produce soda. Hence salt in a dry state 

 is chlorate of soda, and dissolved in water it becomes muriate of soda. Its 

 action in the soil depends ori the effect which the muriate of soda has on the 

 carbonate of lime ; the latter, as we have before observed, being found in 

 almost all soils. By the contact of these two salts, their acids and bases are 

 interchanged, and the compounds which are the result are carbonate of soda 

 and muriate of lime. Hence, as chalky soils abound more in carbonate of 

 soda than any others, salt is supposed to be most beneficial to them. Salt 

 applied in large quantities, it is well known, destroys plants ; and hence 

 it has been used in gardening, both in a dry and liquid state, to kill weeds 

 and worms in gravel- walks, which it does most effectually. It has been used 

 also for washing salads and other vegetables when gathered for the kitchen, 

 when they are supposed to contain snails, worms, or insects. It forms a 

 direct constituent of some marine plants, and plants of saline marshes or 



