TRANSACTIONS OF SECTION B. 573 



The pendulum begins its swing from the electro-positive side ; lithium, next to 

 hydrogen in simplicity of atomic weight, is now formed ; then glucinvim, boron, 

 and carbon. Definite quantities of electricity are bestowed on each element at the 

 moment of birth, on these quantities its atomicity depends,' and the types of 

 monatomic, diatomic, triatomic, and tetratomic elements are fixed. The electro- 

 negative part of the swing now commences ; nitrogen appears, and notice how 

 curiously position governs the mean dominant atomicity. Nitrogen occupies the 

 position below boron, a triatomic element, therefore nitrogen is triatomic. But 

 nitrogen also follows carbon, a tetratomic body, and occupies the fifth position 

 counting from the place of origin. How beautifully these opposing tendencies are 

 harmonised by the endowment of nitrogen with at least a double atomicity, and 

 making its atom capable of acting as tri- and pentatomic. With oxygen (di- 

 and hexatomic) and fluorine (mon- and heptatomic) the same law holds, and one- 

 half oscillation of the pendulum is completed. Again passing the neutral line the 

 electro-positive elements sodium (monatomic), magnesium (diatomic), aluminium 

 (triatomic), and silicon (tetratomic) are successively formed, and the first com- 

 plete oscillation of the pendulum is finished by the birth of the electro-negative 

 elements, phosphorus, sulphur, and chlorine ; these three — like the corresponding 

 elements formed on the opposite homeward swing — having each at least a double 

 atomicity depending on position. 



Let us pause at the end of the first complete vibration and examine the result. 

 We have already formed the elements of water, ammonia, carbonic acid, the atmo- 

 sphere, plant and animal life, phosphorus for the brain, salt for the sea, clay for the 

 soUd earth, two alkalies, an alkaline earth, an earth, together with their carbonates, 

 borates, nitrates, fluorides, chlorides, sulphates, phosphates, and silicates, sufficient 

 for a world and inhabitants not so very different from what we enjoy at the present 

 daj". True, the human inhabitants would have to live in a state of more than 

 Arcadian simplicity, and the absence of calcic phosphate would be awkward as far 

 as bone is concerned. But what a happy world it would be ! No silver or gold 

 coinage, no iron for machinery, no platinum for chemists, no copper ^\"ire for 

 telegraphy, no zinc for batteries, no mercury for pumps, and, alas ! no rare earths 

 to be separated. 



The pendulum does not, however, stop at the end of the first complete vibration ; 

 it crosses the neutral point, and now the forces at work are in the same position as 

 they were at the beginning. Had everything been as it was at first, the next 

 element again would have been lithium, and the original cycle would have recurred, 

 repeating for ever the same elements. But the conditions are not quite the same ; 

 the form of energy represented by the vertical line has declined a little — the 

 temperature has sunk — and not lithium, but the one next allied to it in the series 

 comes into existence — -pottassium, which may be regarded as the lineal descendant 

 of lithium, with the same hereditary tendencies, but with less molecular mobility 

 and higher atomic weight. 



Pass we rapidly along the to and fro curve, and in nearly every case the same 

 law is seen to hold good. The last element of the first complete vibration is 

 chlorine. In the corresponding place in the second vibration we do not have an 

 exact repetition of chlorine, but the very similar body bromine ; and when for a 

 third time the position recurs we see iodine. I need not multiply examples. 



In this far-reaching evolutionary scheme it could not come to pass that the 



' ' Nature presents us with a single definite quantity of electricity. . . . For each 

 chemical bond which is ruptured within an electrolyte a certain quantity of electricity 

 traverses the electrolyte, which is the same in all cases.' — G. Johnstone Stoney, 

 ' On the Physical Units of Nature.' British Association Mectitiff, 1874, Section A. 

 Phil. Mag., May 1881. 



'The same definite quantity of either positive or negative electricity moves 

 always with each univalent ion, or with every unit of affinity of a nuiltivalent ion.' — 

 Helmholtz, Faraday Lecture, 1881. 



' Every monad atom has associated with it a certain definite quantity of electricity ; 

 every dyad has twice this quantity associated with it ; every triad three times as 

 much, and so on.' — 0. Lodge, 'Or Electrolysis,' British Association Iteport, 1885. 



