PROBLEMS OF CHEMISTRY 317 



process of subdivision be carried ? Is there any limit ? The 

 atomists held that, after a time, particles would be reached 

 so small that they could not be made smaller. But their 

 opponents said, "No! this is inconceivable. Matter must 

 be infinitely divisible." As neither side could prove the 

 other wrong, the question under discussion was well adapted 

 to the purposes of controversy. 



The atom of to-day is a scientific abstraction. Many 

 facts have been brought to light that make it appear cer- 

 tain that matter is not continuous is not capable of infinite 

 subdivision. Dalton, the Quaker schoolmaster of Man- 

 chester, was the first one to bring the atom down to the 

 earth and make it a useful idea. How he did this cannot 

 be shown here. Suffice it to say, the atomic theory pro- 

 posed by Dalton in the early years of the century lives 

 to-day, and is stronger than it has ever been, notwithstand- 

 ing the efforts that have been made to show that it is built 

 upon sand. It has been, and is to-day, an extremely useful 

 theory. Whether it will always continue to be so is another 

 question, and one that need not bother us. It is believed 

 that each elementary substance that is to say, each chem- 

 ical element consists of minute particles that are not 

 broken up in the course of chemical changes. These par- 

 ticles that remain intact are the atoms of chemistry. Some 

 such theory is absolutely necessary to account for the 

 fundamental laws of chemistry. 



Into what thin air we enter, when we begin to speak of 

 the properties of the individual atom, will appear when it 

 is stated that, according to the calculations of Lord Kelvin, 

 the molecule of hydrogen, which is at least twice as large 

 as its atom, is of such size that it would take 50,000,000 of 

 them placed in a row to occupy an inch ! To be sure, most 

 atoms are larger than those of hydrogen, but there are few 

 so large that it would not be necessary to have about a 

 million of them to occupy an inch. What sense is there in 

 talking about such things? We shall never be able to see 

 them, or to prove that they exist. True, but the conception 



