BOB] 



192 



[ROB 



water through triassic sandstone. Brit. Assoc. 

 Rep., 1878, pp. 397-419. 



Roberts, Isaac. 9. Boring on East Hoyle 

 Bank. Liverpool, Lit. Phil. Soc. Proc., 32, 

 1878, pp. Ixxxviii-xcii. 



1O. Influence of the Sun and Moon on the 



level of underground water. On the attractive 

 influence of the Sun and Moon in causing tides, 

 and the variations in atmospheric pressure and 

 rainfall, causing oscillations in the underground 

 waters in porous strata. Symons, Meteorol. 

 Mag., 18, 1883, pp. 133-134; Brit. Assoc. Rep., 

 1883, p. 405. 



Roberts, James. A useful theorem in the theory 

 of attractions. Quart. Joura. Math., 17, 1881, 

 pp. 149-153. 



Roberts, Ralph Augustus. On the tangents 

 drawn from a point to a nodal cubic. [1881.] 

 London Math. Soc. Proc., 12 (1880-81), pp. 99- 

 101. 



2. Note on a system of cartesian ovals 



passing through four points on a circle. [1881.] 

 London Math. Soc. Proc., 12 (1880-81), pp. 200 

 -201. 



3. On tangents to a cubic forming a pencil 



in involution. [1881.] London Math. Soc. Proc., 

 13 (1881-82), pp. 25-27. 



4. On polygons circumscribed about a 

 cuspidal cubic. [1882.] London Math. Soc. 

 Proc., 13 (1881-82), pp. 148-153. 



5. On unicursal twisted quartics. London 

 Math. Soc. Proc., 14 (1882-83), pp. 22-34, 308- 

 314. 



6. On polygons circumscribed about a 



tricuspidal quartic. [1882.] London Math. 

 Soc. Proc., 14 (1882-83), pp. 56-62. 

 Roberts, Robert Dames. Evidence bearing upon 

 the position of the Twt Hill conglomerate. Geol. 

 Mag., 8, 1881, pp. 194-197. 



2. The basement beds of the cambrian in 



Anglesea and Carnarvonshire. Geol. Mag., 8, 

 1881, pp. 439-441. 



3. The Twt Hill conglomerate and the 



base of the cambrian. Geol. Mag., 9, 1882, pp. 

 114-118. 



4. Some points in the geology of Anglesey. 



Geol. Mag., 9, 1882, pp. 152-154, 362-363. 



Roberts, Samuel. 39. Note on the expression 

 of the length of the arc of a cartesian by elliptic 

 functions. [1873-75.] London Math. Soc. Proc., 

 5 (1873-74), pp. 6-9 : 6 (1874-75), p. 200. 



4O. On the parallel surfaces of developables 



and curves of double curvature. [1874.] London 

 Math. Soc. Proc., 5 (1873-74), pp. 90-94. 



41. On a simple condensing collector for 



frictional electrical machines. Phil. Mag., 47, 

 1874, pp. 49-50. 



42. On a simplified method of obtaining 



London Math. Soc. Proc., 6 (1874-75), pp. 101- 

 1 lo. 



Roberts, Samuel. 43. On the quartic surface 

 reciprocal to the surface of centres of a central 

 conicoid. Quart. Journ. Math., 13, 1875, pp. 

 188-197. 



44. On three-bar motion in plane space. 



[1875.] London Math. Soc. Proc., 7 (1875-76), 

 pp. 14-23. 



45. Further note on the motion of a plane 



under certain conditions. [1876.] London Math. 

 Soc. Proc., 7 (1875-76), pp. 216-225. 



46. Notes on the normals of conies. [1877.] 



London Math. Soc. Proc., 9 (1877-78), pp. 65 

 -75. 



47. On the decomposition of certain 

 numbers into sums of two square integers by 

 continued fractions. [1878.] London Math. 

 Soc. Proc., 9 (1877-78), pp. 187-196. 



48. Geometrical note on triangles inscribed 



in a circle and circumscribed about a parabola 

 with reference to the nodes and foci of a three- 

 bar curve. Quart. Journ. Math., 15, 1878, pp. 

 52-55. 

 49. On the sextic curves represented by 



and the correlative quartics. Quart. Journ. 

 Math., 15, 1878, pp. 224-230. 



SO. On forms of numbers determined by 

 continued fractions. [1878.] London Math. 

 Soc. Proc., 10 (1878-79), pp. 29-41. 



51. Note on certain determinants connected 

 with algebraical expressions having the same 

 form as their component factors. Messenger of 

 Math., 8, 1879, pp. 138-140. 



52. On the impossibility of the general 



extension of EULER'S theorem on the product of 

 two sums of four squares to the product of two 

 sums of 2 m squares where m is >3. Quart. 

 Journ. Math., 16, 1879, pp. 159-170; 17, 1881, 

 pp. 276-280. 



53. Note on a problem of FIBONACCI'S. 

 [1879.] London Math. Soc. Proc., 11 (1879-80), 

 pp. 35-44. 



54. Note on the integral solution of 



x*-2Py s = - z* or + 2* in certain cases. [ 1 880. ] 

 London Math. Soc. Proc., 11 (1879-80), pp. 83 

 -87. 



55. On an immediate generalization of 



local theorems in which the generating point 

 divides a variable linear segment in a constant 

 ratio. Amer. Journ. Math., 3, 1880, pp. 336- 

 343. 



56. On certain series whose coefficients 



are the inverses of binomial coefficients. Mes- 

 senger of Math., 9, 1880, pp. 166-170. 



57. On certain tetrahedra specially related 



the order of algebraical conditions. [1875.] to four sphere s meeting in a point. [1881.] 



