large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_01_asimov_64kb_173
large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_01_asimov_64kb
English
12904
A number of elements had atomic weights that were nearly whole numbers on the "oxygen = 16" standard. A NUMBER OF ELEMENTS HAD ATOMIC WEIGHTS THAT WERE NEARLY WHOLE NUMBERS ON THE OXYGEN EQUALS SIXTEEN STANDARD
drogen does. The ratio of its atomic weight to that of other elements is also more often a whole number. In working out the atomic weight of elements it was therefore more convenient to set the atomic weight of oxygen at a whole number than that of hydrogen. Berzelius did this, for instance, in the table of atomic weights he published in 1828. At first he called the atomic weight of oxygen 100. Then he decided to make the atomic weights as small as possible, without allowing any atomic weight to be less than 1. For that reason, he set the atomic weight of oxygen at exactly 16 and in that case, the atomic weight of hydrogen had to be placed just a trifle higher than 1. The atomic weight of hydrogen became 1.008. This system was retained for nearly a century and a half. Throughout the 19th century, chemists kept on working out atomic weights more and more carefully. By the start of the 20th century, most elements had their atomic weights worked out to two decimal places, sometimes three.  THAT OF OTHER ELEMENTS IS ALSO MORE OFTEN A WHOLE NUMBER IN WORKING OUT THE ATOMIC WEIGHT OF ELEMENTS IT WAS THEREFORE MORE CONVENIENT TO SET THE ATOMIC WEIGHT OF OXYGEN AT A WHOLE NUMBER THAN THAT OF HYDROGEN BRAZILIUS DID THIS FOR INSTANCE IN THE TABLE OF ATOMIC WEIGHTS HE PUBLISHED IN EIGHTEEN TWENTY EIGHT AT FIRST HE CALLED THE ATOMIC WEIGHT OF OXYGEN ONE HUNDRED THEN HE DECIDED TO MAKE THE ATOMIC WEIGHTS AS SMALL AS POSSIBLE WITHOUT ALLOWING ANY ATOMIC WEIGHT TO BE LESS THAN ONE FOR THAT REASON HE SET THE ATOMIC WEIGHT OF OXYGEN AT EXACTLY SIXTEEN AND IN THAT CASE THE ATOMIC WEIGHT OF HYDROGEN HAD TO BE PLACED JUST A TRIFLE HIGHER THAN ONE THE ATOMIC WEIGHT OF HYDROGEN BECAME ONE POINT ZEROZERO EIGHT THIS SYSTEM WAS RETAINED FOR NEARLY A CENTURY AND A HALF THROUGHOUT THE NINETEENTH CENTURY CHEMISTS KEPT ON WORKING OUT ATOMIC WEIGHTS MORE AND MORE CAREFULLY BY THE START OF THE TWENTIETH CENTURY MOST ELEMENTS HAD THEIR ATOMIC WEIGHTS WORKED OUT TO TWO DECIMAL PLACES SOMETIMES THREE
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