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O.34

are in all probably fewer than 600 chemical elements, reckoning that few of those of atomic weights higher than radium are unknown to us; and that not 500 of them dart through the Universe too swiftly to be held down by the earth's gravitation, Coronium being the slowest of these. The smallness of this number, considering that near a generation ago the mere catalogue of the known carbon compounds filled a thick octavo volume, and that, in fact, the different amino acids alone must be more numerous than that list,—bespeaks the simplicity of their constitution; and yet the greatest mathematician will confess the utter hopelessness of attempting thoroughly to comprehend the constitution of the hydrogen atom, the simplest of all on earth.

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