CHEESE RENNET. 



CHEMISTRY. 



the sinker of the chessel. The piston is raised 

 or depressed by a small pinion attached to a 

 ratchet wheel and malleable iron lever, three 

 feet in length. The lever is grooved in seve- 

 ral places on the upper side to hold the ring of 

 the weight for increasing or diminishing the 

 jpower, in proportion to its distance from the 

 ratchet wheel. The weight of this press is 

 about two stone, cost 11. 4s. pressure 20 tons. 

 (Martin Doyle's Pract. Husb. ; Prof. Lowe's Elem. 

 ofJlgr.} See DAIBT. 



CHEESE RENNET, or YELLOW BED- 

 STRAW (Galium verum), is a perennial plant, 

 common in waste places and the borders of 

 fields, flowering in July and August. The 

 stem, which is woody and much branched, 

 rises eighteen inches, and sends off, in the 

 same plane, narrow, deep green, deflexed 

 leaves, rough with minute points, each tipped 

 with a hair. The flowers are golden yellow, in 

 dense tufted panicles, and smell strongly of 

 honey in the evening and before rain. The 

 flowers of this weed were formerly used in 

 Cheshire for curdling milk. (Paxton's Sot. Diet.; 

 Smith's Ens;. Flor. vol. i. p. 208.) 



CHELIDONIUM. From ckeledon, a swallow; 

 it being said to flower at the arrival and wither 

 at the departure of the swallows. See CELAN- 

 DINE. 



CHELONE (Chelone barbata. From chelone, 

 a tortoise ; to the back of which the helmet of 

 the flowers is fancifully compared). Known 

 in Pennsylvania and other Middle States by the 

 names of Shell-flower, and Snake-head. This 

 plant is a native of North America, and a 

 hardy perennial ; blowing beautiful red flowers 

 in July and August. It loves shade and mois- 

 ture, and grows three feet high. The white 

 chelone is hardy, and likes any soil. The 

 downy chelone blows a flower which is yellow 

 inside, and light purple outside. It is propa- 

 gated by seed, and by separating the roots in 

 autumn. It belongs to a hardy herbaceous 

 genus, that ought to have a place in every col- 

 lection : the species succeed well in a mixture 

 of peat and loam. (Paxton's Sot. Diet.) 



CHEMISTRY. The importance of this 

 science to the agriculturist no intelligent mo- 

 dern farmer will doubt. Its triumphs in the 

 cause of the cultivator have been far too many 

 for him to hesitate in acknowledging the obli- 

 gation. I have, in this work, under the heads 

 EARTHS, ANALYSIS OJF SOILS, GASES, WATER, 

 SALTS, ORGANIC CHEMISTRY, &c., endeavoured, 

 to the best of my power, to illustrate some of 

 the many chemical facts on which the success- 

 ful practice of agriculture depends ; and to 

 these I must refer the farmer. Most of the 

 substances belonging to our globe, says Davy, 

 (Chem. Philosophy, p. 1), are constantly under- 

 going alterations in sensible qualities, and one 

 variety of matter becomes, as it were, trans- 

 muted into another. Such changes, whether 

 natural or artificial, whether slowly or rapidly 

 performed, are called chemical ; thus, the gra- 

 dual and almost imperceptible decay of the 

 leaves and branches of a fallen tree exposed to 



rthe atmosphere, and the rapid combustion of 

 wood in our fires, are both chemical operations. 

 The object of chemical philosophy is to ascer- 

 tain the causes of all phenomena of this kind, 

 318 



J and to discover the laws by which they are 

 governed. . The ends of this branch of know- 

 ledge are the applications of natural substances 

 to new'uses, for increasing the comforts and 

 enjoyments of man; and the demonstration of 

 the order, harmony, and intelligent design of 

 the system of the earth. The foundations of 

 chemical philosophy are observation, experi- 

 ment, and analogy. By observation, facts are 

 distinctly and minutely impressed on the mind. 

 By analogy, similar facts are collected. By 

 experiment, new facts are discovered; and, in 

 the progression of knowledge, observation, 

 guided by analogy, leads to experiment ; and 

 analogy, confirmed by experiment, becomes 

 scientific truth. To give an instance, who- 

 ever will consider with attention the slender 

 green vegetable filaments (Conferva rivi'lm-ix) 

 which in the summer exist in almost all 

 streams, lakes, or pools, under the different 

 circumstances of shade and sunshine, will dis- 

 cover globules of air upon the filaments ex- 

 posed under water to the sun, but no air on the 

 filaments that are shaded. He will find that 

 the effect is owing ,to the presence of light. 

 This is an observation; but it gives no informa- 

 tion respecting the nature of the air. Let a ; 

 wine-glass filled with water be inverted over 

 the conferva thus acted upon by the light. The 

 air-bubbles, as they rise, will collect in the 

 upper part of the glass ; and, when the glass is j 

 filled with air, it may be closed with the hand,] 

 placed in its usual position, and an inflamed 

 taper introduced into it: the taper will burn 

 with more brilliancy than in the atmosphere. 

 This is an experiment. If the phenomena are 

 reasoned upon, and the question is put, whether 

 all vegetables of this kind, in fresh or in salt 

 water, do not produce such air under like cir- 

 cumstances, the inquirer is guided by analogy; 

 and, when this is determined to be the case by 

 new trials, a general scientific truth is esta- 

 blished, that all confervoe in the sunshine 

 produce a species of air (oxygen gas) which 

 supports flame in a superior degree : a fact 

 which has been shown to be the case by vari- 

 ous minute investigations. 



By such researches the chemist ascertains 

 the composition and uses of the various other 

 gases, and also of the earths, metals, and salts, ol 

 which the materials of the earth we inhabit are 

 composed ; delightful inquiries, which will well 

 repay the cultivator in more ways than one for 

 the labour he may bestow upon them. They 

 will speedily teach him that nothing in this 

 world of ours is ever lost or destroyed ; that the 

 decaying materials of his most noisome ma- 

 nures speedily again make their appearance in 

 new forms, and in salubrious and fragrant 

 plants ; that the expired breath of himself and 

 his live-stock is the inhaled food of all vegeta- 

 tion ; and that vegetables purify the very air 

 which animals have vitiated. And again, the 

 correct rotation of crops, the use of permanent 

 or earthy additions to the soil, (which see), the 

 fattening of live-stock, the origin of diseases, 

 are a few only of the facts connected with the 

 cultivation of the soil which the chemist's 

 operations illustrate. "The nature of soils" 

 (as it is remarked by Mr. G. W. Johnson), "of 

 manures, of the food and functions of plants, 



