716 HENRY SOTHERAN & CO., 140, STRAND, W.C, and 43, PICCADILLY, W. 



14293 ROBERTS (E.) Famous Chemists [from G. E. Stahl to Victor Meyer], or. 8vo. c/., 2* 1911 



14294 ROBERTS (H. A.) Treatise on Elementary Dynamics, dealing with Relative Motion 

 mainly in Two Dimensions, with numerous diagrams, cr. 8vo. cl.y Is Qd (p. 4^ 6c?) 1900 



14295 ROBERTS (Isaac, F.R.s.) Photographs of the Nebula in the Pleiades, of Stars in the 

 Surrounding Regions and of Spurious Nebulosity, with plate, 8vo. (pp. 6), sewn, Is Qd 1898 



14296 Selection of Photographs of Stars, Star-Clusters, and Nebula, with Informa- 

 tion concerning the Instruments and the Methods employed in the Pursuit of Celestial Photo- 

 graphy, ivithdS collotype plates from photographs taken by the author with his 20" Reflector, roy. 

 4to. cl. (scarce), £2. Is 1894 



' Presented to Adam Sedgwick, M. A., f.r.s. with compliments of the author, Isaac Roberts, June ]894'. — hiscr. on 

 note paper. 



' In March, 1885, Sir Howard Grubb mounted for Dr. Isaac Roberts, at Maghull, near Liverpool (his observatory has 

 since been transferred to Crowborough in Sussex), a silver-on-glass reflector of 20" aperture, constructed expressly for use 

 in celestial photography. A series of nebula-pictures, obtained with this fine instrument, have proved highly instructive 

 both as to the structure and extent of these wonderful objects ; above all one of the great Andromeda nebula.' — Miss 

 Agnes M. Gierke. 



' With a view of obtaining very prolonged exposures, Roberts spared no trouble or expensft in providing his telescope 

 with an exceedingly perfect driving-clock, and at length Grubb succeeded in supplying him with one, electrically controlled, 

 which met his requirements. With this Roberts has made successful exposures, even 4 hours in length, with astonishing 

 results, particularly in respect to nebulai. The Pleiades have been shown to present an almost continuous mass of 

 nebulous matter ; the great Orion nebula has been traced far beyond the old limits, whilst the Andromeda nebula, ' now 

 for the first time shown in an intelligible form ', has proved to be a vast Saturniform body. ... A single plate exiwsed on 

 a region in Cygnus has shown more tlian 16,003 stars ; whilst the spiral nebula in Canes Venatici has been depicted with 

 most wonderful distinctness.' — G. F. Chambers, F.R.A.S. 



14297 : William Herschel's 52 Observed Nebulous Regions, compared with I. R.'s Photo- 

 graphs, with 2 plates, 8vo. (pp. 9), sew7i. Is Hd 1902 



14298 ROBERTS (Samuel, f.r.s. ; p.l.m.s.) On certain Tetrahedra specially related to Four 

 Spheres meeting in a Point, 8vo. (pp. 4), sewn, \s [1878] 



14299 On the Mechanical Description of some Species of Circular Curves of the Third 



and Fourth Degrees, with plate, 8vo. (pp. 12), unbound, Is 6d 1869 



With a Paper ' On the Generalization of the Theory of Polars,' by W. K. Clifford, f r.s. (pp. 4). 



14300 On the Motion of a Plane under certain Conditions, with diagrams, 8vo. (pp. 33), 



sewn, 2? [1871] 



14301 Note on the Expression of the Length of the Arc of a Cartesian by Elliptic 



Functions, 8vo. (pp. 4), unbound, is " [1873] 



14302 Note on Normals and the Surface of Centres of an Algebraical Surface, 8vo. (pp. 6), 



sewn. Is 6rf [1873] 



14303 Note on the Pluckerian Characteristics of Epi- and Hypo-Trochoids and Allied 



Curves, 8vo. (pp. 4), unbound, \s [1873] 



14304 Note on the Symmetrical Expression of the Constants in the Equations of 



Algebraical Curves, 8vo. (pp. 8), unbound, \sQd , 1856 



14305 Sur I'Ordre des CONDITIONS de la Coexistence des Equations AlgiSbriques ji 



Plusieurs Variables, 4to. (pp. 14), sewn, \s dd [1867] 



14306 On the Order of certain Systems of Algebraical Equations, 8vo. (pp. 13), unbound, 



2s [1867] 



With a Paper ' On a General Tlieory of Anharmonics,' by W. K. Clifford, f.r s. (pp. G). 



14307 On the Order and Singularities of the Parallel of an Algebraical Curve, 8vo. 



i^x 12), sewn. Is es . [1871] 



14308 On the Ovals of Descartes, with diagrams, 8vo. (pp. 21), sewn, Is 6d [1870] 



14309 On Parallel Surfaces, 8vo. (pp. 20)', sewn, Is ed [1873] 



14310 On the Parallel Surfaces of Conicoids and Conics, 8vo. (pp. 35), sewn, 2s [1872] 



14311 On the Parallel Surfaces of Developables and Curves of Double Curvature, 



8vo. (pp. 5), unbound, Is [1874] 



14312 On the Pedals of Conic Sections, with 2 diagrams, 8vo. (pp. 12), sewn. Is Qd [1870] 



14313 Surle25e Probleme du 5^ LiVRE de DiOPHANTE et la Solution par Fermat, roy. 



Svo. (pp. 7), sewn. Is 6d [Nancy, 1888] 



14314 On Professor Cremona's Transformation between Two Planes, and Tables 



relating thereto, 8vo. (pp. 19), sewn. Is &d [1872] 



14315 On a Simplified Method of Obtaining the Order of Algebraical Conditions, 8vo. 



(pp. 12), sewn. Is 6d [1875] 



14316 On Three-Bar Motion in Plane Space, with diagrams, Svo. (pp. 10), sewn. Is 6d 



[1876] 



14317 On the Transformation of Coordinates, 8vo. (pp. 23), sewn. Is 6d [Cambridge, 1857] 



14318 ROBERTS (W. H.) The Scottish Ale-Brewer : a Practical Treatise, with a Simplified 

 Process of Sparging, and the Method of conducting Slow Fermentation : containing also Four 

 Tables of Original Gravities and Attenuations, etc. etc., first edition, with woodcuts, 8vo. cl., 

 6s 6d Edin., 1837 



' Scotch Ale deservedly held, as it still holds, the first [? strongest] rank amongst fermented liquors of British manufacture.' 



14319 Third Edition : The Scottish Ale-Brewer and Practical Maltster . . . with the Method 



in the Making and Managing of India Pale Ale, and Supplement on the Relative Value of Malt 

 and Sugar, with woodcuts, Svo. cl., 7s Qd ibidem, 1847 



14320 ROBERTS (William Ralph Westropp, pr., t.c.d.) On the Reduction of an Integral, 

 8vo. (pp. 7), sewn, with author's inscr. and MS. notes {only 50 copies privately printed). Is 6d 



Dublin, 1900 



