i8 THE CREATION OF MATTER 



weighing is necessary. A chemical balance is therefore 

 an instrument of exquisite delicacy. It is suspended, 

 when in use, on a fine knife edge of agate, and removed 

 from it on every occasion when it has served its purpose, 

 to prevent wear and tear. Its arms are measured with 

 greatest care, to ensure their perfect equality in substance 

 and in length. By these means friction is reduced to a 

 minimum, and its sensibility to the least addition or 

 withdrawal intensified to a maximum. It is capable of 

 determining weight to the one-millionth of the substance 

 weighed. 



Indirectly, and in different ways, on rational principles, 

 atoms can be weighed. The weights of sun, moon, and 

 stars can be scientifically determined, and so it is possible 

 to weigh also the smallest particles. It is easy to weigh 

 ounces, pounds, hundredweights, tons. It is not so easy 

 to weigh atoms. But the results are as real, as definite, 

 as certain. The weights are of course comparative. 

 There must be a standard of comparison, and hydrogen, 

 as being the lightest of substances, is adopted. Hydrogen 

 is 1, carbon 12, nitrogen 14, oxygen 16, magnesium 23'94, 

 aluminium 2 7 '3, phosphorus 30, chlorine 35 -5, iron 55*9, 

 zinc 66-9, silver 107, gold 196'2, mercury 199-8, and 

 others between these weights, and above 200. Weigh 

 an equal number of atoms of these elements, and the 

 weights are always according to these proportions. A 

 number of carbon atoms are always twelve times heavier 

 than the same number of hydrogen. Atoms of the same 

 kind are thus practically of the same weight. They are 

 attracted in the same measure by other atoms and aggre- 

 gates of atoms. There is not a billionth of difference 

 between them. Every atom of hydrogen weighs alike. 

 Every atom is fitted to be a standard measure of weight. 

 Every atom of carbon throughout the vast realm of the 



