DRY 



DUC 



incomparably better in the pulveriza- 

 tion produced by hoeing, independent 

 of the clearness from weeds. 



12. The drills give facility for de- 

 positing smaller portions of manure 

 with greater effect. 



A saving of half the seed is also 

 effected. But, on the other hand, the 



and in damp situations, and may he 

 perfectly prevented by saturating the 

 timber with several metallic solutions, 

 of which blue vitriol (sulphate of cop- 

 per), acetate of iron (pyrolignate), and 

 corrosive sublimate are most certain. 

 Allowing wood to be immersed in a 

 cream of lime, in tar, &c., for some 



expense of hoeing wheat, &c., very \ weeks, or perfectly drying and slight- 



much increases the price of cultiva- 

 tion ; although it is, according to the 

 evidence of practical men, repaid by 

 the large increase of crop. 



The soils most benefited by this 

 operation are light, sandy, and calca- 

 reous ; on clays, the treading causes 

 too much stiffening. 



Such crops as beans, pease, cot- 

 ton, turnips, carrots, and beets are 

 now most usually sown in drills with 

 the greatest advantage. Such rough 

 seeds as carrots require to be first 

 well rubbed with sand to remove the 

 spines. 



DRILL ROLLER. A roller fur- 

 nished with a number of sharp rings 

 projecting from the surface, which 

 cut the earth and leave drills to sow 

 seeds in : it is only suitable on light 

 soils. 



DROPSY. See Horse, &c. 



DROSOMETER (from dpoaoc, dew, 

 and/zerpov, a measure). Any arrange- 

 ment for measuring or weighing the 

 quantity of dew falhng at any given 

 time. Dr. Wells's contrivance is the 

 simplest ; he exposed a known weight 

 of dry wool, and afterward weighing 

 it when saturated with dew, obtained 

 a measure of the increase of moist- 

 ure. 



DRUPE. In botany, a one-celled, 

 one or two seeded, fleshy fruit ; as the 

 cherrv, plum, peach. 



DRY DISTILLATION. The same 

 as Destructive Distillation. 



DRYING OIL. This usually 

 means linseed oil which has been 

 boiled with white-lead. It forms the 

 basis of many paints. 



DRY ROT. A rotting or decay of 

 wood, whereby it falls gradually into 

 powder. It is produced by the action 

 of numerous parasitical fungi, prob- 

 ably of the genus Sporolrichum. It is 

 most usually seen in the new wood, 

 X 2 



ly charring the timber, is an easy pre- 

 ventive. The methods of preser- 

 vation by using metallic solutions are 

 termed Kyanizing, and are now ac- 

 complished with extensive machines, 

 for the purpose of expediting the pen- 

 etration of the fluid. In these cases 

 the albumen of the wood, which is 

 most liable to change, is disorgan- 

 ized and rendered nearly incorrupti- 

 ble. See Preservation of Timber. 



DRY STOVE. A hot-house, in 

 which the air is kept very dry for trop- 

 ical plants derived from arid climates, 

 as cactuses. 



DUCK. Many species of the genus 

 Anas. The common duck is econom- 

 ical ; one drake serves eight females. 

 The house should be clean and pro- 

 vided with nests. They are very fond 

 of insects, and slugs, toads, &c. The 

 female lays from fifty to sixty eggs 

 during March to May ; she sets a 

 month, and should be sparingly sup- 

 plied with moist food and kept away 

 from disturbance. The young should 

 not be allowed to go to the water at 

 first, but supplied with a little in a 

 hole : the duck must be kept cooped. 

 The ducklings are first to be fed on 

 bread crumbs soaked in milk, and 

 subsequently used to meal and herbs. 

 The feathers are valuable, and should 

 be plucked as soon as the animal is 

 dead: September and October are the 

 best times. It is usual to hatch ducks' 

 eggs under hens, which are better 

 nurses. The Muscovy being larger, 

 is preferred to the common duck by 

 many, but is not as tender. 



DUCTILITY. The property of be- 

 ing drawn or beaten into a fine film. 

 Gold, platinum, and silver are the 

 most ductile of metals. 



DUCTS. The tubes or tubular 

 vessels found in the wood, roots, 

 leaves, &c., of plants, which do not 



245 



