Energy and Ether. 1033 



Hydrogen, fluorine, &c., are monads. A hydrogen atom therefore 

 cannot be joined directly to more than one other atom. Oxygen is a dyad 

 and has two bonds so that one oxygen atom may be attached to two hy- 

 drogen atoms, forming a molecule of water, the formula being H.,0, 

 and graphically expressed H-O-H, showing two bonds to the 0, and one 

 to each H. 



6 0x7 



Fia. 403. 



The number of bonds or poles possessed by an atom is tbe measure of what is called its 

 valency, which indicates the number of other atoms with which it can be directly 

 joined. Thus H F, H Cl, H Br, and H I are molecules of Hydrogen fluoride, Hydrogen 

 chloride, Hydrogen bromide, and Hydrogen iodide, in which one monovalent atom of 

 Hydrogen is joined to one atom of Fluorine, Chlorine, Bromine, and Iodine, respectively. 

 H 2 O, H 2 S, H 2 Se, H 2 Te, stand for molecules of Hydrogen oxide (water), Hydrogen sul- 

 phide, Selenhydric ucid, and Tellurhydric acid, in which two atoms of monovalent hy- 

 drogen are joined to divalent atoms of oxygen, sulphur, selenium, and tellurium, respect- 

 ively. H 3 N, H 3 P, H 3 As are molecules of Hydrogen nitride (ammonia), Hydrogen phos- 

 phide (phosphine), and Hydrogen arsenide (arsine), which are composed of three atoms 

 of Hydrogen, and one each of trivalent nitrogen, phosphorus and arsenic. H 4 C and HiSi 

 are molecules of Hydrogen carbide (methane) and Hydrogen silicide, composed of four 

 atoms of Hydrogen and one each of tetravalent carbon and silicon, respectively. The 

 graphic expression of one of these formula would be made by a tetrad atom, having a 

 monad atom impaled on each of its four poles ; thus H 



H r-H 



A 



In the possession of multiple poles of chemical affinity, molecules 

 imitate the masses that exhibit multiple poles of magnetic attraction. 

 Multiplicity of polarity is no doubt due to the shape of the body, a 

 mass having four poles has no doubt four corners. 



Again there is a great difference in the force of chemical attraction 

 Some elements have a strong affinity for one another, others have weak 

 affinity for each other, and still others have no affinity for each other at 

 all. Oxygen forms a strong affinity with phosphorus, potassium, &c. , 

 nitrogen and carbon form weak affinities with hydrogen; chlorine :md 

 iodine, &c. , have weak affinities for each other, while oxygen and 

 fluorine, hydrogen and chromium, hydrogen and sodium, &c. , have" no 

 affinity for each other at all. In this too we find the parallel between 

 the magnetic? attraction of masses and the chemical attraction of mole- 

 cules, no two bodies being alike in their electrical characteristics, jind 

 neutral bodies being indifferent to each other. The theory was pro- 

 posed by Berthollet, and has since been verified that chemical action 

 depends on the mass of the elements engaged, as well as upon affinity. 

 As he stated it, "Every substance which tends to enter into combina- 

 tion acts in proportion to its affinity and its mass." He regarded th : s 

 as evidence that chemical affinity is essentially the same as gravitation. 



