MAYER 275 



to the cells. All this and a great deal more, which had 

 either remained questionable or merely isolated fact, 

 was suddenly brought by Mayer, in the most astonishing 

 manner, into a grand connected system. He notices the 

 fundamental importance of the nature of heat, and answers 

 this question by saying: 'Heat is a force; it can be trans- 

 formed into mechanical effect.'^ 



He there sees how heat is transformed in the steam engine 

 into mechanical work, so that a certain number of calories 

 disappear, while a certain other number of metre-kilograms of 

 work appear. He also sees how that product - mass mul- 

 tiplied by square of velocity - likewise denotes a quantity of 

 work; for velocity only results from the expenditure of work, 

 and when the product decreases, some form of work done 

 appears, such as the raising of a body thrown upwards, or in 

 the pendulum; and heat also may be this form of work, as 

 when a moving body comes to rest by friction, or in the case 

 of inelastic collision, where the product also diminishes, while 

 heat is produced, which is not the case in elastic collision. 



He further sees that likewise the mechanical separation of 



^ We say to-day, in the same sense that Mayer used the word 'force,' 

 or 'effect,' rather 'energy,' which expression was introduced much later 

 (Helmholtz still used the expression 'conservation of force'). 'Energy' is 

 stored-up work, and since work is measured by the product of the working 

 force and the distance moved in the direction of this force, work is thus 

 something other than force defined in Newton's sense (as Leonardo 

 already recognised); it is therefore not permissible to use the word force 

 in place of work. Mayer was perfectly clear on his point (as h's publica- 

 tion Remarks on the Mechanical Equivalent of Heat in 185 1 showed in 

 full detail); only he thought that it would be possible to give up Newton's 

 definition of force. This latter fortunately did not happen; instead, it 

 became clear, that Mayer's newly formed concept of stored-up work 

 - in which work appears as a substance unalterable in amount - also 

 needed a new name, and energy was introduced for this purpose. 

 This also again shows us the great novelty of Mayer's achievement; its 

 formation of a new concept required the introduction of a new word. The 

 fact that the concept arrived before the word is a sign of the solidity of 

 scientific investigation at that time, quite by way of contrast in many other 

 cases, where the opposite process so slyly recommended by Mephisto- 

 pheles, takes place: 'for just where ideas are wanting, a new word appears 

 at the right moment' (.Faust I, Fourth Scene). 



