ROB] 



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. Proo., 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. Synions, Meteorol. 



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



1883, p. 405. 

 Roberts, Jam?s. A useful theorem in the theory 



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



pp. 149-153. 

 Roberts, Ralph Augustus. On the tangents 



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



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 Darius. 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, Xaimtel. 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 

 the order of algebraical conditions. [1875.] 



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

 113. 



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 lay 



. 



and the correlative quartics. Quart. Journ. 

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



50. 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'" 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' or 2z* in certain cases. [1880.] 

 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 



to four spheres meeting in a point. [1881.] 



