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



9109 HELMHOLTZ (Hermann Ludwig Ferdinand v.; f.r.s.) Uber die Erhaltung der 

 Kraft, eine physikalische Abhandlung, vorgetragen in der Sitzung der physikalischen Gesell- 

 schaft zu Berlin am 23sten Juli 1847, erste Auflage, 8vo. sewn (very scarce), £1. 1* 



Berlin, 1847 

 The scarce first edition of the work which embodies the author's investigations into the theory of the conservation of 

 energy, whose origination he shares with J. R. v. Mayer, Joule, Lord Kelvin, and Ciausius. 



9110 Handbuch der PHYSIOLOGISCHEN OPTIK ; with 11 plates, and 213 ivoodcuts, roy. 8vo. 



hf. German morocco, uncut, 185 6o? Hamburg, 1867 



First Edition of the author's most important work, the first systematic treatise applying physical laws to the study 

 of the physiology of the eye, and equally valuable for the original discoveries and the historical investigations it 

 contains. 



9111 Die Lehre von den Tonempfindungen, als physiologische Grundlage fiir die Theorie 



der MusiK, 3. nmgearbeitete Aufiage ; ivith 65 ivoodcuts, 8vo. hf. calf, 5s Braunschweig, 1870 



9112 On the Sensations of Tone as a Physiological Basis for the Theory of Music, 



translated from the third German Ed., with additional Notes, and Appendix, by ALEXANDER J. 

 Ellis, f.r.s. [philologist], with 65 woodcuts, thick 8vo. cl., lOs 6d (p. £1. 16s) 1875 



The original contributions by the translator extend to over 160 pages. 



This standard work contains the author's numerous discoveries in physiological acoustics. 



9113 Popular Lectures on Scientific Subjects, translated by E. Atkinson, with Intro- 

 duction by John Tyndall, f.r.s., both series, first English. Editions, with woodcuts, 2 vols, 

 large post 8vo. cl., 8s (p. £1.) 1873-81 



9114 New Uniform Edition, ivith woodcuts, 2 vols, large post 8vo. cl., Is 6d (p. 155) 1884 



9115 First Series only, ivith ivoodcuts, large post 8vo. cL, 3s 6d (p. 12* 6d) 1873 



9116 : McKendrick (John Gray) Hermann Ludwig Helmholtz [with Bibliography], 



portrait, cr. 8vo. cl., 2s 1899 



9117 , Portrait of, engraved on steel by Charles Henry Jeens, proof before letters, 



3s n. d. 



9118 The Same, on India paper, signed by the engraver, 4* 



9119 HELMONT (Jean Baptists van) Works : containing his most Excellent Philosophy, 

 Physick, Chirurgery, Anatomy, wherein the Philosophy of the Schools is examined, their 

 Errors refuted, and the whole Body of Physick reformed and rectified ; being a new Rise and 

 Progresse of Philosophy and Medicine for the Cure of Diseases, and Lengthening of Life, made 

 English by J [oseph] C[onstable] sometime of M[agdalen] H[all?], Oxon., with etched frontis- 

 piece, containing portrait and arms of J. B. and F. M. van Helmont, 3 vols, folio, hf. calf 

 {slightly browned, and front, mounted); RARE, with auto. *W. Hunter' on title, and MS. notes 

 in the same handwriting, £3. 3* L. Lloyd, 1664-2 



Vol II is entitled ' Oriatrike, or Physick Refined,' and v. Ill ' Opuscula Medica Inaudita.' 



9120 Another Issue, with frontispiece of portraits, in one vol. folio, original rough calf 



[front., title, and a few II. mended, but a large copy), £2. 155 1662 



9121 Another Copy, contemporary calf, newly rebacked {fine copy), £3. 3* 



An earlier issue of the foregoing work, without the general title, and address ' To the English J^^eadcr '. 



9122 Ortus Medicine, i. e. Initia Physicae Inaudita, Progressus Medicince Novus, in 



Morborum Ultionem, ad Vitam Longam, edente Francisco Mercuric van Helmont, cum 

 ejus Prsefatione ; Editio nova, cum locupletiori Kerum et Verborum Indice, adauctior et 

 exornatior ; with engraved portrait of author and editor, thick sm. 4to. old calf, £1.1* 



Amst., Lud. Elzevirius, 1652 

 ' He is regarded by some historians of chemistry as the greatest chemist who preceded Lavoisier. He was the first to 

 point out the imperative necessity for employing the balance in chemistry, and by its means showed in many instances 

 the indestructibility of matter in chemical changes. He was the first to coin the word gas (derived according to some 

 from the Greek x^OQ, and according to others from the Dutch geeM), applying it to elastic aeriform fluids. He was also 

 the first to take the melting-point of ice and boiling-point of water as standards for the measurement of temperature. It is 

 in his works that the term saturation is first employed to signify the combination of an acid with a base ; and he was one 

 of the earliest investigators of the chemistry of the fluids of the human body.' 



9123 HELSHAM (Ricliard, m.d., Prof. Nat. Phil. Dubliyi ; friend of Dean Swifc) Course of 

 Lectures in Natural Philosophy, published by Bryan Robinson, m.d., with 11 plates, 8vo. 

 old calf, 4s ed 1739 



9124 Second [last] Edition, with 11 plates, 8vo. old calf, or, hf. calf, 6s 1743 



The appendix contains original problems : ' Of the collision of Non Elastick and Elastick Bodies ', etc. etc. 



9125 HELWING (Georg Andreas) Lithographia Angerburgica, sive Lapidum et Fossilium, in 

 Districtu Angerburgensi et ejus Vicinia, ad III vel IV Milliarium Spatium, in Montibus, Agris, 

 Arenofodinis et in primis circa Lacuum Littora et Fluviorum Kipas Consideratio ; with view of 

 Angerburg, and 10 other copperplates, sm. 4to. old calf {joints cracked), 10s 6c? 



Begiomonti [Konigsberg], 1717 



9126 HEMENWAY (Frank F.) Indicator Practice, and Steam-Engine Economy, with 45 illus- 

 trations, post 8vo. cl., 4s 6d (p. 8s 6d nett) New York, 1886 



9127 HEMMING (George Wirgman; Senior Wrangler; K.c.) Billiards Mathematically 

 Treated, with 2 plates, and diagrams, impl. 8vo. cl. {o.p.), 5s 1899 



Of singularly little interest to the man about town. 



9128 Elementary Treatise on the Differential and Integral Calculus, 2nd [last] 



Edition, with Additions, diagrams, 8vo. cl. {cover slightly damaged), 4s Cambridge, 1852 



Based on the method of limits. 



9129 [HENDERSON (John)] Meteorography, or the Perpetual Weather Almanac, contain- 

 ing nearly Fifty of the Signs which occur before every Change of Weather, engraved and coloured 

 from Nature, with 46 coloured plates, sq. 12mo. cl. {scarce), 10s Qd Edin., 1841 



The author here claims to have discovered how to predict correctly the weather one day, or at most one week, in 

 advance by the state of the sky. 



