Contents of Volume IV. 
21 
PAGE 
PAGE 
70 
251. 
Sur quelques formules pour la différentiation .... 
135 
Tortolini, t. ii. (1859), pp. 214—230 
72 
252. 
Note sur l'équation des différences pour une équation donnée 
de degré quelconque ........ 
150 
74 
Tortolini, t. ii. (1859), pp. 365, 366 
253. 
Sur la courbe parallèle à l'ellipse ...... 
152 
Tortolini, t. in. (1860), pp. 311—316 
78 
254. 
Sur la surface parallèle à l'ellipsoïde ..... 
158 
Tortolini, t. ni. (1860), pp. 345—352 
80 
255. 
On a Problem of Double Partitions. ..... 
166 
Phil. Mag. t. xx. (1860), pp. 337—341 
81 
256. 
On a System of Algebraic Equations ..... 
171 
Phil. Mag. t. xx. (1860), pp. 341, 342 
86 
257. 
On the Cubic Centres of a line with respect to three lines and 
a line . . . . . . 
173 
Phil. Mag. t. xx. (1860), pp. 418—423 
88 
258. 
On a Relation betiveen two Ternary Cubic Forms . 
179 
Phil. Mag. t. xx. (1860), pp. 512—514 
259. 
The Problem of Polyhedra ....... 
182 
92 
Phil. Trans, t. cxlvii. (for 1857), pp. 183—185 
260. 
On the Double Tangents of a Plane Curve .... 
186 
99 
Phil. Trans, t. cxLix. (for 1859), pp. 193—212 
261. 
On the Conic of Five-pointic Contact at any Point of a Plane 
108 
Curve ........... 
207 
Phil. Trans, t. cxLix. (for 1859), pp. 371—400 
112 
262. 
On the Equation of Differences for an Equation of any Order 
and in particular for . the Equations of the Orders two, 
three, four, and five . . . . 
240 
Phil. Trans, t. CL. (for 1860), pp. 93—112 
116 
263. 
Demonstration of a Theorem in Finite Differences . 
Phil. Trans, t. cl. (for 1860), pp. 321—323 
262 
120 
264. 
On an Extension of Arbogast's Method of Derivations 
265 
Phil. Trans, t. CLi. (for 1861), pp. 37—43 
265. 
Addition to the Memoir on an Extension of Arbogast's Method 
123 
of Derivations . . . . . . . 
272 
Now first published, 1891