THE CHEMICAL, ELEMENTS — RAMSAY. 191 



energy at the same rate that gun-cotton does, we should have an 

 undreamed-of explosive; could we control the rate we should have a 

 useful and potent source of energy, provided always that a sufficient 

 supply of radium were forthcoming. But the supply is certainly a 

 very limited one; and it can be safely affirmed that the production 

 will never surpass half an ounce a year. If, however, the elements 

 which we have been used to consider as permanent are capable of 

 changing with evolution of energy; if some form of catalyser could be 

 discovered which would usefully increase their almost inconceivably 

 slow rate of change, then it is not too much to say that the whole 

 future of our race would be altered. 



The whole progress of the human race has indeed been due to 

 individual members discovering means of concentrating energy, and 

 of transforming one form into another. The carnivorous animals 

 strike with their paws and crush with their teeth; the first man who 

 aided his arm with a stick in striking a blow discovered how to con- 

 centrate his small supply of kinetic energy; the first man who used a 

 spear found that its sharp point in motion represented a still more 

 concentrated form; the arrow was a further advance, for the spear 

 was then propelled by mechanical means; the bolt of the crossbow, 

 the bullet shot forth by compressed hot gas, first derived from black 

 powder, later, from high explosives; all these represent progress. To 

 take another sequence: The preparation of oxygen by Priestley 

 applied energy to oxide of mercury in the form of heat; Davy im- 

 proved on this when he concentrated electrical energy into the tip of 

 a thin wire by aid of a powerful batteiy, and isolated potassium and 

 sodium. 



Great progress has been made during the past century in effecting 

 the conversion of one form of energy into others, with as little useless 

 expenditure as possible. Let me illustrate by examples: A good 

 steam engine converts about one-eighth of the potential energy of the 

 fuel into useful work; seven-eighths are lost as unused heat and useless 

 friction. A good gas engine utilizes more than one-third of the total 

 energy in the gaseous fuel; two-thirds are uneconomically expended. 

 This is a universal proposition; in order to effect the conversion from 

 one form of energy into another, some energy must be expended 

 uneconomically. If A is the total energy which it is required to con- 

 vert; if B is the energy into which it is desired to convert A; then a 

 certain amount of energy, C, must be expended to effect the conver- 

 sion. In short, A=B+C. It is eminently desirable to keep C, the 

 useless expenditure, as small as possible; it can never equal zero, but 

 it can be made small. The ratio of C to B (the economic coefficient) 

 should therefore be as large as is attainable. 



The middle of the nineteenth century will always be noted as the 

 beginning of the golden age of science ; the epoch when great generali- 



