108 HENRY SOTHERAN & CO., 140, STRAND, W.C., AND 37, PICCADILLY, W. 



2139 JELLETT (John Hewitt, D.D., Provost T. C. D.) ELEMENTARY TREATISE on the CALCULUS of 

 VARIATIONS, 8vo. cl. (VERY SCARCE), 1. 10s Dublin, 1850 



' This valuable work constitutes the only complete treatise on the calculus of variations in the English langt^ge . . . 

 We strongly recommend the sLudentto master this important volume.' Todhunter's His*, of the Calculus of Variaiiont 



2140 TREATISE on the THEORY of FRICTION, with 30 illustrations, 8vo. cl. (SCARCE), 15* 



ibidem, 1872 



The only extant treatise in English on the theory of friction, considered as a part of rational mechanics. ' Some of the 

 principles contained in the present treatise are believed to be here enunciated for the first time." Preface. 



2141 JENKIN (Henry Charles Fleeming, F.R.S.) BRIDGES : an Elementary Treatise on their CON- 

 STRUCTION and HISTORY (from Ency. Brit.), with Opiates and 133 woodcuts, 4to. cl., 3s 



Edin., 1776 [sic, recte 1876] 



2142 ELECTRICITY and MAGNETISM, 6th or 7th Ed., with 177 woodcuts and diagrams, cr. 8vo. 



cl.,3s6d 1881 or '3 



' Marking a new departure in the exposition of electricity, as the first text-book containing a systematic application of 

 the quantitative methods inaugurated by the British Association Committee on Electrical Standards.' Lord Keldn. 

 The Gth was the last edition revised by the author, and the 7th is a reprint. 



2143 -PAPERS LITERARY, SCIENTIFIC, etc., ed. by SIDNEY COLVIN and J. A. EWING, F.R.S. , 

 with MEMOIR (pp. 170) by ROBERT Louis STEVENSON, with portraits, plates, and numerous 

 diagrams, 2 vols. 8vo. cl., uncut (SCARCE), 1. 105 1887 



Much valued not only for the biography by R. L. STEVEXSON, but also for the high scientific value of the papers them- 

 selves. It includes a 'Note on the Contributions of Fleeming Jenkin to Electrical and Engineering Science', by LORD 

 KELVIN, as well as the author's Papers on ' Telpherage ', Submarine Telegraphy, etc. etc., and a List of his Patents. 



' In practical engineering thoroughness and soundness marked all Jenkin's work. His determinative work in electricity 

 is of the highest value, while his varied originality as an inventor is testified by his 35 British patents, and by his scientific 

 $.' G. T. Bettany. 



2144 : REPORTS of the COMMITTEE on ELECTRICAL STANDARDS appointed by the BRITISH 



ASSOCIATION, revised by LORD KELVIN, J. CLERK MAXWELL, and FLEEMING JENKIN, FF.R.S., 

 with the latter's REPORT on UNITS of ELECTRICAL RESISTANCE, and his CANTOR LECTURES [on 

 SUBMARINE TELEGRAPHY], 7 folding plates, and diagrams, 8vo. cl. (very scarce], 15s 1873 



' The experimental work of first making practical standards, founded on the absolute system, which led to the unit now 

 known as the British Association ohm, was chiefly performed by Clerk Maxwell and Jenkin. The realisation of the great 

 practical benefit which has resulted from the experimental and scientific work of the Committee is certainly due to Jenkin's 

 zeal and perseverance as secretary, and as editor of the Collected Reports . . . The volume of Reports included Jenkin's 

 Cantor Lecture ' On Submarine Telegraphy ', through which the practical applications of the scientific principles . . . 

 became part of general knowledge in the engineering profession '. Lord Kelvin. 



2145 JENNINGS (David ; Independent Minister, Wapping) INTRODUCTION to the USE of the GLOBES 

 and the ORRERY, with plates, Svo. nice copy in old calf, with bookplate of Philip Earl Stanhope, 

 F.R.S., 5s 1747 



With appendix ' attempting to explain the account of the first and fourth days' work of Creation in the first chapter 

 of Genesis'. 



2146 JENSEN (C. O., Copenhagen) GRUNDRISS der MILCHKUNDE und MILCHHYGIENE ; with 22 

 illustrations, 8vo. sewn, 3? (p. M. 4.80.) Stuttgart, 1903 



2147 JENYNS [later BLOMEFIELDJ (Leonard, pr.} OBSERVATIONS in METEOROLOGY, relating to 

 Temperature, the Winds, Atmosphere, Weather Changes, etc., post 8vo. cl., 3s (p. 105 Qd) 1858 



2148 JEPH3ON (Thomas, B.D.) The FLUXIONAL CALCULUS, with diagrams, 2 vols. 8vo. hf. calf 

 (scarce), 8* 6d 1826-30 



'I have not confined myself to the Newtonian doctrine of limits, but have introduced the principles of La Grange's 

 Theory of Functions.' Preface. Vol. II contains the Integral Calculus, Differential Equations, and the Calculus of 

 Variations. 



2149 JERVIS (Col. Henry Jervis-White, R.A., M.P.) Our ENGINES of WAR, and how we got to 

 make them, with numerous ivoodcuts chiefly from old illustrations, large post Svo. cl. (scarce), 

 5s 1859 



A good historical sketch, illustrating especially the gradual evolution of firearms. 



2150 JESSOP (Francis) PROPOSITIONES HYDROSTATIC^: ad illustrandum ARISTARCHI Samii System* 

 destinatse, et quaedam Phoenomena Naturae Generalia ; with diagrams, 4to. (pp. 34), sewn, 3s Qd 



Londini, 1687 



2151 JEVONS (William Stanley, F.R.S.) ELEMENTARY LESSONS in LOGIC : Deductive and Induct- 

 ive, with VOCABULARY of Logical Terms, fcap. Svo. cl., 2s 1870 or 74 



2152 The PRINCIPLES of SCIENCE : a Treatise on Logic and Scientific Method ; LIBRARY 



EDITION, with front, of the Logical Machine, 2 vols. Svo. cl., uncut (out of print), 15s (p. 1. 6*) 1874 



2153 ANOTHER COPY, new hf. brown calf extra, uncut, t. e. g., 1. 2s Qd 



2154 NEW EDITION, printed in smaller type, with front., post Svo. cl., Is (p. 12? 6d) 1877, or 1879 



His most important work, with illustrations derived from almost every branch of science, wherein 'he developed his 



theory of logic and scientific method, and of its applications beyond and, so to speak, above the sphere of physical 

 science alone. It proved more stimulative to mathematicians than to metaphysicians '. D. N. B. 



' W. 8. Jevons in his Principles of Science founds induction upon the theory of inverse probability.' Prof. Cajori. 



2155 PURE LOGIC, or the Logic of Quality apart from Quantity, with Remarks on Boole's 



System and on the relation of Logic and Mathematics, first edition, post Svo. cl., with author's 

 inscr. on flyleaf, 5s 1861 



Founded on Boole's ' Laws of Thought' (q. v. ante), but divested of the latter's mathematical dress, c which, to say the 

 least, is not essential to it.' Preface. 



2156 The SUBSTITUTION of SIMILARS, the True Principle of Reasoning, derived from a Modifi- 

 cation of Aristotle's Dictum, with front, of the Logical Abacus, 12mo. cl. (VERY SCARCE), 15s 1869 

 ' Designed as an uncompromising step towards the liberation of logic from the ban of metaphysics, and its establishment 

 as an exact science.' A. W. Ward. 



2157 , LETTERS and JOURNAL of, edited by his WIFE, with steel portrait by Stodart, Svo. cl., 



Is (p. 145) 1866 



Containing a complete bibliography, an account of his unfinished projected publications, his religious opinions, etc. etc. 



