makes it easier to investigate physical phenomena, affects not merely the technique of the science, but may originate ideas which will ultimately revolutionize our philosophy of the universe. I feel sure, for example, that many of the ideas we now possess regarding atoms and their structure originated in the study of phenomena which would not have been discovered but for Sir James Dewar's invention for producing very high vacua by means of charcoal cooled by liquid air.
It is not to the theorist alone that scientific ideas owe their origin; the inventor of a new piece of apparatus, the mechanic whose skill enables him to construct the exceedingly sensitive instruments which detect effects so small that they would escape a coarser measure, all play their part in the progress of scientific ideas.
It is often assumed that the mechanical arts minister to nothing but material wants, that telephones and telegraphs, motor-cars and aeroplanes merely make life more luxurious or exciting; they may do this, but the engineering skill and activity of which they are the symbol have other and more intellectual effects, and, by the aid they afford us in investigating material phenomena, may profoundly affect the most philosophical and abstract science.
To return, however, to the Atomic Theory: it is not until the seventeenth century that we find any serious use was made of it for the explanation of physical phenomena, and to that great philosopher, Robert Boyle, who was so closely connected with Oxford, belongs the credit of being the first to use the theory in a way at all analogous to the methods of modern physics. Indeed Boyle's point of view is quite surprisingly modern. Newton gave the theory his powerful support, and taught that cohesion and chemical affinity were the