xii Contents 



FIRST PUBLISHED PAPER ON ELECTRICITY P . 33 



AN ATTEMPT TO EXPLAIN SOME OF THE PRINCIPAL PHENOMENA 

 OF ELECTRICITY, BY MEANS OF AN ELASTIC FLUID 



From the Philosophical Transactions for 1771 (pp. 584-667) 

 Part I 



ARTICLES 



Hypothesis 1-6 



Repulsion of a cone on a particle at the vertex 7-1 1 



Force between two bodies over or under charged 13-15 



Equilibrium of the electric fluid 16.1? 



Repulsion of a spherical shell . . . . . . . 18,19 



Equilibrium of electricity in a globe 20-27 



Two plane parallel plates 28-38 



Canals of incompressible fluid 39"53 



Pressure of electric fluid against a surface 54 



Circular disk 55~66 



Charges of similar bodies as the n - i power of their corresponding diameters, and 



independent of the material of which they are made 67-72 



Charge of a thin flat plate independent of its thickness 73 



Two parallel circular plates 74-83 



Equilibrium of electricity in bodies communicating by a canal is independent of 



the form of the canal 84-93 



Whether the conditions of equilibrium are the same for two bodies communicating 



by a conducting wire as if they communicated by a canal of incompressible 



fluid 94-96 



Molecular constitution of air 97 



Part II p. 66 



CONTAINING A COMPARISON OF THE FOREGOING THEORY WITH EXPERIMENT 



i . Conductors and non-conductors 98 



Electric properties of air and vacuum 99. >oo 



Positive and negative electrification 101-105 



2. Attraction and repulsion 106-117 



Electrometer in electrified air n? 



3. On the cases in which bodies receive electricity from or part with it to the air 1 18-122 



4. Effect of points on discharge 123-126 



5. Canton's and Franklin's experiments 127 



6. On the Leyden vial 128-133 



7. Wilcke and /Epinus's experiment of electrifying a plate of air (Mem. Berl. 



1756, p. 119) 134 



8. Electric spark i3S-'39 



PRELIMINARY PROPOSITIONS . . p. 82 



From the MS. in the possession of the Duke of Devonshire, No. 4 



Prop, xxix (Fig. i). If the fluid uniformly spread on a circular plate is to that collected 

 in the circumference as p to i the capacity of the plate is to that of the globe as p + i 



to 2p + 1 '4 



Prop. xxx. Capacity of two disks at a finite distance 141 



Cor. i. Capacity in terms of p H 2 



Cor. 2. Capacity when the density is supposed uniform 143 



Cor. 3. The place in which the canal meets the disk is indifferent only when the fluid 



is in equilibrium ......... '44 



Lemma xn (Fig. 2). Repulsion of a particle on a column 145 



