Ml 



RAPE-SEED. 



RATE. 



943 



assist the effects of saltpetre or of nitrate of soda, where these salts are 

 applied. The cultivation of rape or cole for spring food cannot be too 

 strongly recommended to the farmers of heavy clay soils. 



RAPE-SEED. The Braisica napiti, the plant which produces the 

 rape-seed, and which is of the cabbage tribe, is cultivated like Cole, or 

 Colza (Bratfiea napus tatira), for the sake of its seeds, from which oil 

 is extracted by grinding and pressure. It is also extensively cultivated 

 in England for the succulent food which its thick and fleshy stem and 

 leaves supply to sheep when other fodder is scarce. The mode of 

 cultivation of the colza and rape for seed is nearly the same. The 

 colza takes a longer time to come to maturity, and produces more seed. 

 The rape grows on less fertile soils, and may be sown in spring as well 

 as in autumn. Both are hardy, and resist the winter's frost. 



The rape seed imported in the years 1857-8-9 averaged 283,000 qrs. 

 per annum : it is admitted free of duty. 



RAREFACTION is an augmentation of the intervals between the 

 particles of aeriform fluids, so that the same number of particles are 

 made to occupy a volume greater than that under which they were 

 previously contained. The term is used in opposition to condensa- 

 tion, and in the same sense as dilatation, which last is applied both 

 to fluids and solids. Rarefaction or dilatation is caused by a repulsive 

 power existing either in the particles of bodies or in those of the 

 caloric between them, by which power the particles are made to 

 recede from one another when not prevented by some external resist- 

 ance. [ATTRACTION.] 



The experiments of Lavoisier and Laplace have shown that, between 

 the temperatures of freezing and of boiling water, the dilatations of 

 all metals and of the fluids called non-elastic are constantly propor- 

 tional to the increments of temperature ; but beyond the temperature 

 of boiling water the experiments of Dulong and Petit indicate that 

 the dilatations increase in a higher ratio. A remarkable circumstance is 

 observed in the state of water when near congelation. On being 

 cooled to a temperature of about 38'8 of Fahr., its volume remains 

 stationary through a small range, and in this state water seems to have 

 attained its maximum of density ; for, on continuing the cooling pro- 

 cess, the water begins to expand, and it continues to do so until it is 

 converted into ice. In fact, just before water freezes it occupies a 

 space as great as it did at 48. If water at 39'2 be taken as 1, at 32" 

 its density = 0-99988. 



From the experiments of M. Gay-Lussac and Dr. Dalton it has 

 been ascertained that, under equal external pressures, the rarefactions 

 of all dry gases and of the aeriform substances produced by the evapo- 

 ration of liquids are equal at equal temperatures, between the points 

 of freezing and boiling water, and that they vary in volume propor- 

 tionally to the increments of heat expressed by the expansions of 

 mercury in the thermometer. [AiB ; HEAT; GAS; PNEUMATICS.]! 



The density or closeness of the aerial particles in any given portion 

 of the atmosphere depends on the pressure or weight of the column 

 of ah- above the given point ; and by the law of Boyle or Mariotte, 

 whatever be tho temperature, provided it be constant, the density is 

 proportional to the pressure ; or, conversely, the rarefaction is 

 inversely proportional to the pressure. It has been proved '[PNEU- 

 MATICS] that the densities of the strata of air decrease upwards in a 

 geometrical progression when the altitudes of the strata increase by 

 equal increments; and this is equivalent to saying that the rare- 

 factions of the air at such altitudes increase in a geometrical progres- 

 sion. Now if A be any point on the surface of the earth, and c any 



point above it, the formula A o (in fathoms) = 10670 x log. <tensi1 !/ "' A 



density at c 



[PNEUMATICS], will afford the means of computing the'rarefaction of 

 the air at any point c, when its height above A is given. But if the 

 density at A be considered as unity (the temperature being =55) the 

 equation may be transformed into 



AC 



loSFo 



( =log. _ J = log- rarefaction at c, 



V. derurity at c / 



in which, substituting for A c any given value in fathoms, the rare- 

 faction may be found. For example, let A c = 3212 fathoms (3'6S 

 mik*); then the second member of the equation will become '30103 

 (=lpg. 2), which show* that at the height of about 3 j miles the rare- 

 faction of the atmosphere is twice as great as at the surface of the 

 earth ; and by forming the progression of heights 



, 3-65 , 7'3 , 14-6, &c. in miles, 

 wo have for the corresponding rarefactions 



1 , 2 , 4 , 8, Ac. 



For the rarefaction of the air in an air-pump, after any number of 

 strokes of the piston, see AiR-Pmp. 



The limits to which rarefaction may be carried arc unknown, but 

 the experiments of Mr. Boyle and others have proved that, by simply 

 removing the external pressure, air may be so rarified that a given 

 volume of the same density as at the surface of the earth will occupy 

 ft volnme more than 13,000 times as great. It has been however dis- 

 covered that at very high degrees of rarefaction the elasticity o the 

 air decreases in a higher ratio than the density ; and this may 

 serve to prove that rarefaction cannot take place to an infinite 

 extent. [ATMOSPHERE.] 



RASP. [FILE MANUFACTURE.] 



RASPBERRY. The species from which the cultivated varieties of 

 this fruit have been derived is the Rubus Idreus, a native of Britain 

 and also of various other parts of Europe. The wide dispersion of 

 the species is easily accounted for from the fact of its seeds resisting 

 the powers of digestion in an eminent degree. 



For a selection, the following varieties may be enumerated : Red 

 Antwerp, Yellow Antwerp, Barnet, Double Bearing, and Wilmot's early 

 Red. 



The best soil for raspberries is a light rich loam. They will thrive well 

 in sandy peat, provided it is not too dry. In all cases the ground for 

 a plantation should be well trenched and manured previous to planting. 

 The plants from suckers, of which there are generally abundance, 

 should be planted in rows five or six feet apart, and four feet from 

 plant to plant in the row. When planted they should be cut to within 

 six inches of the ground ; for although this is not absolutely essen- 

 tial, yet by so doing the shoots for the following season are greatly 

 strengthened. 



Pruning should be performed in autumn. It consists in first 

 clearing off all dead portions, and retaining only from four to six 

 of the strongest summer shoots of each plant, which should be 

 shortened according to their strength, generally at a bend, which 

 indicates where the shoot becomes weak, near the extremity. In the 

 following summer the shoots just mentioned bear the fruit, whilst 

 others spring up at their base for a succession ; and in all cases succes- 

 sion shoots should be disposed so as neither to crowd the fruiting 

 portion nor each other. Stakes should be driven for the support of the 

 plants, to which they should be loosely bound. 



The ground of a raspberry plantation should be kept loose and sup- 

 plied with well-rotted manure, but in so doing a fork should be used 

 hi preference to a spade, in order to preserve the roots as much as 

 possible, and the roots should not be at all disturbed after active vege- 

 tation takes place in spring. N ^withstanding the best management 

 in these respects, it becomes adviseable to make a new plantation in 

 fresh soil after four or five years ; for the roots diffuse themselves so 

 thoroughly in every portion of the soil near the stools, that it soon 

 becomes exhausted. 



The fruit of the raspberry is extensively used in a variety of ways, 

 both by the cook and the confectioner, and also in the preparation of 

 cordial spirituous liquors. 



RATAFIA is a liqueur prepared by flavouring sweetened spirit 

 with various kinds of fruit. There are many varieties, generally 

 named after the fruit which is employed : Ratafia de Cassia has 

 cherries ; Ratafia de Curafoa has the peels of Portugal oranges ; 

 Ratafia d' Angellque has Angelica seeds; Ratafia d'Anis has aniseed; 

 and so on. There are ratafias not only of fruits but of seeds, berries, 

 flowers, balsams, and other vegetable products. There are ratafias, for 

 instance, of cherries, quinces, raspberry, juniper, walnuts, peach and 

 apricot kernels, coffee, cocoa, clovepinks, Seville orange peel, orange 

 flowers, violets, Tolu balsam, &c. All these ratafias have spice and 

 sugar added to them. The French liqueurists are skilled in this as in 

 most other branches of delicate distillation and making of essences. 

 Many English processes of this kind come under the name of rectifying, 

 as described under DISTILLEBT. 



RATE, an assessment levied upon property. Rates are of various 

 kinds, and are denominated with reference to the objects to which 

 they are applied. 



Church-rates are payable by the parishioners and occupiers of tho 

 land within a parish, for the purpose of repairing, maintaining, and 

 restoring the body of the church and the belfry, the churchyard fence, 

 the bells, seats, and ornaments, and of defraying the expenses attend- 

 ing the service of the church. The duty of repairing and rebuilding 

 the chancel devolves on the rector, or vicar, or both together, in pro- 

 portion to their benefice, where there are both in the same church. 

 But by custom the parishioners may be liable to repair the chancel ; 

 and in London there is a general custom to that effect. Church-rate 

 exists in England by virtue of the common law ; nothing is known as 

 to its commencement or introduction. 



In the early church there appears to have been a division of tho 

 tithes either tripartite, one portion to the clergy, one to repairs of 

 tho church, and one to the poor ; or quadripartite, one to the bishop, 

 the other three to the clergy, the church, and the poor. At that time 

 the bishop resided at the cathedral church, together with his clergy, 

 and on liim devolved the duty of repairing the church, caring for the 

 poor, and supplying ecclesiastical ministry. It was then the duty of 

 every Cliristian man to pay to the bishop not only the decimal, or 

 tithes, but also the ecclesife census, church-scot, and the nummus 

 eleemosynarius (alms money). The object to which church-scot was 

 devoted is not known; but church-rates, or something equivalent, 

 certainly appear to have been in existence as a payment by the laity, 

 independent of tithes, in the time of Canute, whose 63rd law, " de fano 

 reficiendo," states that all persons ought of right to contribute to the 

 repair of churches. 



Church-rates are imposed by the parishioners themselves at a meet- 

 ing summoned by the churchwardens for that purpose, and a man- 

 damus is grantable to compel such meeting to be held. If the parisli 

 fail to meet, the churchwardens may impose a rate, but if the meeting 

 should assemble, it rests with the parishioners themselves to determine 



