64 G. F. C. SEARLE, M.A., F.R.S., ON THE 
has not stopped here, and has not left us without some sign-posts 
to guide us in our perplexity. I shall now endeavour to 
indicate some results obtained from experimental work which 
lead to conceptions shedding a little light upon the nature and 
character of the universe. 
§ 5. Nature of Matter—In the bodies around us, on the earth 
or in the sky, whether they be inanimate or whether they be 
living organisms of any kind, we see a bewildering variety of 
substances. But the labours of chemists have led to the belief 
that all bodies are built up of a comparatively small number of 
elements, such as oxygen, carbon, or iron, and have shown that, 
if the elements be arranged in a series according to a certain 
law, there are very remarkable relations between the properties 
of an element and its place in this series. The existence of 
gaps in this series was thought to indicate that some elements 
remained to be discovered, and the theory of the series enabled 
the general character of the missing elements to be clearly 
deseribed. The predictions have been confirmed by the actual 
discovery of some of the missing elements. These results of 
chemical science at once simplify our ideas about the material 
bodies around us, for instead of thinking of countless millions 
of different substances we need only think of about one hundred. 
That the elements found on the earth occur in the sun and stars 
is shown by the spectroscope and by chemical analysis, which 
proves that many meteorites which have fallen on the earth are 
almost identical in composition with the most deep-seated 
terrestrial rocks. 
In the case of helium, the existence of the gas was first 
revealed by spectroscopic examination of the sun, in whose 
spectrum a line was found which did not correspond to any 
terrestrial element then known; the name of helium was 
given to the element causing the line. Helium has now 
been found in terrestrial minerals, and has been liquefied by 
Kammerlingh Onnes at Leiden, the temperature of the liquid 
being only three or four degrees above the absolute zero of 
temperature. This extremely low temperature, the lowest 
reached, so far, in any experiments affords a strange contrast to 
the temperature of 5000° Centigrade or more which prevails 
in the sun, where helium was first discovered. 
The numerical relations between the elements suggest that 
they are all built up of some primordial substance. The most 
promising speculation is that which regards a molecule as 
consisting of a larger or smaller number of minute parts, 
separated by relatively large distances, these parts being 
