1S38J 



FARMERS' REGISTER 



687 



probably, all other substances, receive very weak 

 and evanescent niufinelistn, whicli seems to diU'er 

 in intensity l()r every body. Magnetism is capable 

 of being commnnicated from bodies endowed 

 willi it, to oiliers that do not possess it, and is pro- 

 duced whenever concentrated electricity passes 

 throngh space, its sphere of action or communica- 

 tion beino- at right angles to tlie course of the elec- 

 tricity. Thus a bar of steel, placed transversely 

 over a wire conveying an electrical shock, becomes 

 a magnet. The connexion of magnetism and 

 electricity is of recent discovery, and the fact which 

 perved to established it was made known by M. 

 Qi]rsled, a Danish philosopher. It will ultimately 

 probably tend to a more intimate accjuaintance witli 

 the nature of these two extraordinary agents. The 

 attractive powers of the magnet may be made use 

 of to show the existence of iron in soils, as will be 

 mentioned more particularly hereafter. 



The different powers that have been thus gene- 

 rally described continually act upon common mat- 

 ter so as to change its form, and produce arrange- 

 ments fitted (or the purposes of lile. Bodies are 

 either simple or compound. A body is said to be 

 simple, when it is incapable of being resolved into 

 any other forms of matter. Thus, gold or silver, 

 though they may be melted by heat, or dissolved in 

 corrosive menstrua, yet are recovered unchanged 

 in their properties, and they are said to be simple j 

 bodies. A body is considered as compound, when 

 two or more distinct substances are capable of 

 being produced from it : thus marble is a compound 

 body, lor by a strong heat it is converted into lime, 

 and an elastic fluid is disengaged in the process ; 

 and the proof of our knowledge of the true com- 

 position of a body is, that it is capable of being re- 

 produced by the same substances as those into 

 which it had been decomposed ; thus, by exposing 

 lime for a long while to the elastic fluid disengaged 

 during its calcination, it becomes converted into a 

 substance similar to powdered marble. The term 

 element has the same meaning as simple or unde- 

 compounded body ; but it is applied merely with 

 reference to the present state of chemical know- 

 ledge. It is probable that, as yet, we are not ac- 

 quainted with any of the true elements of matter: 

 many substances, formerly supposed to be simple, 

 have been lately decompounded, and the chemical 

 arrangement of bodies must be considered as a 

 mere expression of facts, the results of accurate 

 statical experiments. 



V^egetable substances in general are of a very 

 compound nature, and consist of a great number of 

 elements, most of which belong likewise to the 

 other kingdoms of nature, and are found in various 

 forms. Their more complicated arrangements are 

 best understood after their simpler forms of com- 

 bination have been examined. 



The number of bodies which 1 shall consider as 

 at present undecomposed, are, as was stated in 

 the introductory lecture, five acidifying or solvent 

 substances, eight inflammable bodies, and forty 

 metals.* 



In most of the inorganic compounds, the nature 

 of which is well known, into which these elements 

 enter, they are combined indefinite proportions; 

 so that, il' the elements be represented by numbers, 

 the proportions in which they combine are ex- 

 pressed either by those numbers, or by some sim- 

 ple multiples of them. 



* Now forty-two.— Firff note, ante. 



I shall mention, in a few words, the character- 

 istic properties ol" the most important simple sub- 

 stances, and the numbers representing the propor- 

 tions in which they combine in those cases where 

 they have been accurately ascertained. 



1. O.ri/jS^c/i Ibrms about one-fill h of the air of our 

 atmosphere. It is an elastic fluid, at all known 

 temperatures. Its specific gravity is to that of air 

 as 10,967 to 10,000. It su|)ports combustion with 

 much more vividness than common air; so that 

 if a small steel wire or a watch-spring, having a 

 bit of inllamed wood attached to it, be intioduced 

 into a bottle filled with the gas, it burns with 

 great splendor. It is respirable. It is very 

 slightly soluble in water. The number repre- 

 senting the proportion in which it combines is 15. 

 It may be made by heating a mixture of the mine- 

 ral called manganese and sulphuric acid together 

 in a proper vessel, or by heating strongly red lead, 

 or red precipitate of mercury. 



2. Chlorine is, like oxygen, a permanent elastic 

 fluid. Its color is yellowish green; its smell 

 IS very disagreeable ; it is not respirable; it sup- 

 ports the combustion of all the common inflam- 

 mable bodies except charcoal ; its specific gravity 

 is to that of air as 24,677 to 10,000 ; it is soluble 

 in about half its volume of water, and its solution 

 in water destroys vegetable colors. Many of 

 the metals (such as arsenic or copper) take fire 

 spontaneously when introduced into a jar or bot- 

 tle filled with the gas. Chlorine may l)e procured 

 by heat in rr together a mixture of spirits of salt, 

 or muriatic acid, and manganese. The number 

 representing the proportion in which this gas enters 

 into combination is 67. 



3. Fluorine, or the fluoric principle. This sub- 

 stance has such strong tendencies to combination, 

 that as yet no vessels have been (bund capable of 

 containing it in its pure form. It may be obtained, 

 combined with hydrogen, by applying heat to a 

 mixture of fluor, or Derbyshire spar, and sulphuric 

 acid ; and in this state it is an intensely acid com- 

 pound, a little heavier than water, and which be- 

 comes still denser by combining with water. The 

 existence of fluorine as an element is proved by its 

 expulsion from certain compounds by chlorine, and 

 by its transfcM-ence from place to place. In attempts 

 made to confine it, so as to examine its properties, 

 it always combines with, or decomposes the vessels 

 employed ; so that, as yet, its physical qualities are 

 unknown : 16 is an approximation to the number 

 representing it. 



4. Iodine. This substance is procured from the 

 ashes of marine plants, afier the extraction of the 

 carbonate of soda, by acting upon them by sul- 

 phuric acid. It appears as a dark-colored solid, 

 having the color and lustre of plumbago : its spe- 

 cific gravity is about 4 ; that of water being 1. It 

 fuses at a low temperature, and at a heat above 

 that of boiling water becomes a violet-colored gas. 

 It forms an active acid by uniting to hydrogen. 

 The alkaline metals burn, when heated in it. It 

 unites to all the metals upon which its action has 

 been examined. 



5. Brome. This body has been very recently 

 discovered in sea-water. It is in its nature analo- 

 gous to iodine, and resembles a compound of these 

 two bodies. It is a dense liquid, and forms an 

 orange-colored gas by a gentle heat. 



6. Hydrogen, or inflammable air, is the lightest 

 known substance ; its specific gravity is to that of 

 air as 732 to 10,000. It burns by the action of an 



