1 38 TEE POPULAR SCIENCE MONTHLY 



application does not explain cosmic phenomena, though difficulties even 

 here were suggested, but even if it account for the action of molar 

 objects, i. e., those objects which can be weighed, measured and handled, 

 it does not answer the questions which are put to us by the world of 

 atoms. The study of chemistry and the queries raised by its revelations 

 compelled the defenders of Newton's theories as a sufficient explanation 

 of all phenomena in the heavens and on earth to enter upon a renewed 

 investigation of the basis on which they rest, and to give patient con- 

 sideration to the phenomena of the atomic world. At length, and 

 because some other action than that of gravity was needed to explain 

 molecular phenomena, the relation of atoms to each other, the phenom- 

 ena of magnetism and electricity, what is known as the atomic theory 

 was suggested and very generally received, not, however, as setting aside 

 any truths discovered by Newton or involved in the astronomical 

 theory, but as supplementing it and accounting with something like 

 reason for the molar and molecular phenomena which it overlooked or 

 did not recognize as existing. 



This atomic theory is not an entirely modern theory. Empedocles of 

 Sicily, who lived in the fifth century before Christ, accepting four primal 

 elements, earth, air, fire and water, explained their modifications and 

 their actions one upon the other, by assuming the existence of two 

 principles, love and hate, attraction and repulsion, which are constantly 

 in operation and which create the forms we behold and account for all 

 the activity in the universe. The atomic theory developed, far more 

 fully than by Empedocles, by Democritus of Abdera of the same cen- 

 tury and defended by him with a wealth of learning possessed by no 

 other man of his time gained wide acceptance. In its modern form the 

 theory secured recognition in France and Germany earlier than in Eng- 

 land. The exact methods of chemists and mathematicians, first in 

 France then in Germany, led to the belief that matter is not a single 

 piece of something in empty space, but is made up of a multitude of 

 individual and indivisible particles which only partially fill this space, 

 which is filled by that indefinable something which we call ether and 

 which we affirm to be necessary both for sight and hearing. 



As chemistry was more earnestly and wisely studied, as the laws of 

 the combination of so-called elemental substances were better under- 

 stood, men of science became less and less unwilling to admit the inade- 

 quacy of Newton's theory of gravitation as an explanation of all phe- 

 nomena and the more ready to accept a theory which explained, as it 

 seemed to them, the movements in the molecular world, and which, if 

 matter is composed, as was asserted, of atoms, might explain conditions 

 everywhere. Berzelius of Sweden demonstrated the truth of the 

 theory by his wonderful experiments. Dalton's theory of atomic weights 

 was accepted as in harmony with what seemed to be facts. Van't Hoff 

 discovered, so it is believed, laws governing the arrangement of elements 



