TRANSACTIONS OF SECTION A. 587 



Next ns regards Potential. This term is used in Dynamics, Electricity, and 

 Magnetism to designate physical quantities of different dimensions; but in all it 

 is that factor of energy which, in order to convert.it into energy, requires to be 

 multiplied — 



In Dynamics, by a mass. 



In Electricity, bj' a quantity of electricity. 



In Magnetism, by a quantity of magnetism. 



This may be stated conveniently by saying that — ■ 



In Dynamics, Potential is the clynaonic energy-factor. In Electricity, Potential is 

 the electric energy-factor. In Magnetism, Potential is the magnetic energy -factor. 

 Now a similar treatment of the term accelerator would at once carry out con- 

 sistency in our nomenclature, would point attention to the true relation between 

 these three sciences, and would free us from one part of the misuse of the word 

 force which is now prevalent. If this suggestion be adopted, we shall speak of — 



The dynamic accelerator, viz., that force-factor which requires to be multiplied 



by mass to convert it into a force ; 

 The electric accelerator, viz., th&i force-factor which requires to be multiplied 



by a quantity of electricity to convert it into a force ; and 

 The magnetic accelerator, viz., that f or ce-f actor yihich requires to be multiplied 



by a quantity of magnetism to convert it into a force. 



And these terms will take the place of what are now miscalled the Electric Force m 

 an Electric Field, and the Magnetic Force in a Magnetic Field ; physical quantities 

 which are in reality not forces at all, but force-factors. 



There will then remain only one, but it is the greatest offender of them all, viz., 

 Electro-motive Force — an abominable term, since it is not a force, nor even a force- 

 factor. It is in reality an energy-factor. AVhy not substitute the term Potency or 

 Potential Range, which would exactly describe what it is, and which would offer 

 the additional convenience of enabling us to .speak, not only of the Potency 

 of a battery or dynamo, extending over the entire current from pole to pole, but 

 also of the Potential Range of each piece of apparatus introduced into the circuit 

 extending from the place where the current enters it to the place where it emerges ? 

 It is often convenient to be able to speak of this concisely and without periphrasis. 

 The phrase jjotewcy of a battery seems the most appropriate one for indicating how 

 much work the battery compels each unit of electricity that traverses the circuit 

 to do. This is what the term ought to imply ; and the term Potency does so 

 without introducing a false analogy like the term Pressure which is sometimes 

 used. 



18. On a Nomenclature for very much Facilitating the Use of Systematic 

 Measures. By G. Johnstonk Stoney, M.A., D.Sc, F.R.S. 



In this communication the author recommended certain prefixes and affixes, 

 which he had been engaged for several years in testing, and which provide a means 

 of avoiding periphrases and of speaking and thinking concisely about matters with 

 which modern science has frequently to deal. The syllables suggested are — 



Hyper-, -ein, -at, -o-, -el, and -ane. 



The metric system of weights and measures furnishes a complete decimal series 

 of lengths and masses, and of the physical quantities derivable from them, such as 

 volume, density, &c. : i.e., it presents us not only with the metre, the gram, the 

 cubic metre, and so on, but also with all the decimal multiples and submultiples of 

 each of these. Moreover, it only needs to use the metric system with the second 

 as our unit of time to have an equally complete series of every other physical 

 quantity, such as density, velocity, force, and energy in dynamics, along with the 

 various other physical magnitudes with which the sciences of electricity and 

 magnetism are separately concerned. 



