d 



NATURE 



\March 13, 1879 



THE FIRST OF THE TWO LECTURES 



(At KILBURN TOWN HALL) on 



"THE CIRCLE AND STRAIGHT LINE," 



By JOHN HARRIS, is now ready ; containing: — 



Introductory Remarks on the Nature of Geometry. 



The Genesis of the Circle. 



The Fallacy in Legendre's supposed Demonstration of the Circle's Ratio. 



PVice, in cloth, ds. 

 Also, 



''GEOMETRICAL DEMONSTRATION OF 

 THE CIRCLE'S RATIO." 



Price, in wrapper, zj. dd. 

 VVERTHEIMER, LEA, & CO., Circus Place, Finsbury. 



84 pp., with 136 Plates, demy 8vo, cloth, 30^. 



PHOTOGRAPHED SPECTRA. One 



Hundred and Thirty-six Photographs of Metallic, Gaseous, and other 

 Spectra printed by the Permanent Autotype Process, with Introduction, 

 Description of Plates, and Index, and with an extra Plate of the Solar 

 Spectrum (showing bright lines), compared with the Air Spectrum. By 

 J. RAND CAPRON, F.R.A.S. 



" . ... Mr. Capron has earned the thanks of spectroscoplsts for the 

 large amount of useful work which he has performed for them in the way 

 of preliminary investigation. No exact scale or measurement accompany 

 the photographs, and they will be chiefly useful in indicating by comparison 

 with each other the lines which belong to particular metals, and the con- 

 ditions under which particular l.nes are produced But although no 



exact measurements are given, and although the photographs vary very 

 perceptibly in length, nearly all show lines which can be used as reference 

 lines, by measurement from which the wave-lengths of the metal lines can 



be determined The advantages of the photographic method are 



noticed by the author as follows : — ' Absolute truth is everything in spectro- 

 scopic work, and the very best draughtsman working with the most perfect 

 micrometer cannot, even at the expense of a vast amount of labour, equal 

 in accuracy a good photograph of a set of spectral lines.' .... The pho- 

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 is, as <ar as we know, the first extensive series of measurements of spectra 

 obtained by the ignition of substances in the electric arc." — Philosophical 

 Magazine. 



London : E. & F. N. SPON, 46, Charing Cross. 



MR. OAKLEY COLES' WORKS. 



In preparation. Third Edition, demy 8vo. 

 DEFORMITIES OF THE MOUTH, their Mechanical 

 Treatment. With an Appendix of Illustrative Cases. London : 

 Churchill, New Burlington Street. 



Opinions of the Press on the First and Second Editions. 

 LANCET, November 28, 1868. — " The work is full of useful information 



of every day utility to the practitioner." 



LANCET, July o. 1870, •• 'The Second Edition of this work shows 

 that the author has continued to devote himself with 2eal to the investigation 

 and treatment of a very interesting class of cases. We recommend the 

 work to the study of both Surgeons and Dentists." 



BRITISH JOURNAL OF DENTAL SCIENCE, August, 1870. 

 — "The Second Edition bears upon its pages the most satisfactory evidence 

 of the industry and zeal with which he has followed up the study and prac- 

 tice of the specialty he has devoted himself to with so much success 



Altogether we must heartily congratulate Mr. Coles on this creditable com- 

 pletion of a work which cannot but redound to his credit, wherever it is 

 kno\vn." 



A MANUAL OF DENTAL MECHANICS. With 



150 Illustrations. Churchill, New Burlington Street. 

 Opinion of the Press. 

 AMERICAN DENTAL REGISTER, November, 1874.— " The 

 work we regard as a very valuable one to the student, and, indeed, for the 

 Practitioner. It should be in every Dentist's library." 



NOTES FOR DENTAL STUDENTS. 2s. Qd. 



Butcher, 4, Crane-court, Fleet Street. 



Opinion of the Press. 



BRITISH JOURNAL OF DENTAL SCIENCE, August, 1876. 



— " We cordially welcome this useful little book Of great value 



to those preparing for the Dental Diploma We hope there will 



soon be a Second Edition needed." 



THE DOCTOR, September, 1876.— " Carefully arranged and very 

 complete. Indeed they seem to try to take in rather more than sufficient for 



Dental students We have no other fault to find with this note-book, 



which appears a model of what such a work should be." 



THE MOUTH AND TEETH DURING PREG- 



NANCY. Reprinted by permission from the Transactions of the 

 Odontological Society. Pp.31. Price is. 6d. London: Wyman and 

 Sons, Great Queen Street. 



Opinion of the Press. 



THE BRITISH MEDICAL JOURNAL.— "The author has 



evidently paid considerable attention to the subject, and gives many useful 



hints as to the management and relief of the distressing toothache and 



neuralgia complicating pregnancy. . ... . The remarks on treatment are 



practical, and will repay perusal The practitioner will do well to 



csrr)' out the suggestions offered by the author. 



MINERALOGY AND GEOLOGY. 



24 assorted Minerals for Blowpipe Experiments, with printed List, in 

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 THOMAS J. DOWNING, 

 38, WHISKIN STREET, LONDON, E.C. 

 catalogues free. 



SHEPPEY FOSSILS. 



W. H. SHRUBSOLE, Shhernbss-on-Sea, respectfully intimates that 

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" NOTES ON THE GEOLOGY OF SHEPPEY " post free on appli- 

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MINERALOGY AND GEOLOGY. 



A New List of Collections of Fossils, Minerals, and Rocks now ready, 

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JAMES R. GREGORY, 



MUSEUM OF GEOLOGY. 



88, CHARLOTTE STREET, FITZROY SQUARE. 



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DRAPER'S INK (DICHROIC). 



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.THE 



^65 ASTRONOMICAL TELESCOPE 



HAS A 3-INCH OBJECT-GLASS. 



Which shows the Ring of Saturn, Belts of Jupiter, and separates the 

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S. & B. SOLOMONS, 



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