336 
Proceedings of the Royal Society 
Table (b ). — Variations in Electromotive Force caused by varying the 
amount of Iodine dissolved in a solution containing *33 grms. of 
Znl 2 in 1 grm. of water. 
Electromotive Force in Volts. 
1*287 
1-271 
1-271 
1-268 
1-259 
1-238 
1-221 
Grms. of Iodine in 1 c.c. 
•309 
-155 
•077 
-037 
•018 
•005 
•0006 
Table (c). — Variations in Electromotive Force caused by varying the 
strength of the Iodide of Zinc in a cell containing -014 grms. of 
Iodine in 1 c.c. 
Electromotive Force in Volts. 
1-075 
1-303 
1-594 
On subtracting these from the 
cuprous iodide members, we get 
•686 
•667 
•719 
Grms. of Znl 2 in 1 grm. of water. 
3-870 
•118 
D.W* 
* Iodine calculated to "014 grams. 
8. On Expressions for the Areas of Rectilineal Figures. 
By A. H. Anglin, M.A., LL.B., &c. 
I. When the straight lines forming the sides of the figure are 
referred to two given straight lines at right angles in the plane of the 
figure— without reference to the co-ordinates of its angular points. 
1. Take OX and OY, two straight lines at right angles to one 
another in the plane of the 
figure, as axes of reference ; and 
let the straight lines forming 
the triangle ABC (fig. 1) meet 
them in the points A 1? A 2 , A s 
and in B x , B 2 , B 3 respectively, 
the distances from O of the former being in descending, and of the 
latter in ascending order of magnitude. 
