33^ 



NATURE 



[August 2, 1888 



2. Zinc and Platinum -with Hydrochloric Acid. — With the 

 astatic galvanometer, between 1 in 9,300,000 and 9,388,185 

 parts ; and with the reflecting one, between 1 in 15,500,000 and 

 23,250,000 parts. 



3. Magnesium and Platinum with Bromine. — With the 

 astatic galvanometer, between 1 in 310,000,000 and 344,4/14,444 

 parts. 



4. Zinc and Platinum with Chlorine. — With the astatic 

 galvanometer, between I in 1,264,030,000 and 1,300,000,000 

 parts. 



5. Magnesium and Platinum with Chlorine. — With the astatic 

 galvanometer, between I in 17,000,000,000 and 17,612,000,000 

 parts ; and with the reflecting one, between 1 in 27,062,000,000 

 and 32,291,000,000 parts of water. 



Every different soluble substance requires a different propor- 

 tion, and with unlike substances the difference of proportion is 

 extremely great. With solutions of neutral salts, the proportion 

 of substance required to upset the balance is large ; for instance, 

 with chlorate of potash, a zinc-platinum couple, and the astatic 

 galvanometer, it lay between 1 part in 221 and 258 parts of 

 water. 



The degree of sensitiveness of the balance is usually greater, 

 the greater the degree of chemical affinity the dissolved substance 

 has for the positive metal and the less it has for the negative 

 one. 



By first bringing the balance with a magnesium-platinum 

 couple and the astatic galvanometer nearly to the upsetting-point 

 by adding I part of chlorine to 17,612,000,000 parts of water, 

 and then increasing the proportion to 1 in 17,000,000,000, the 

 influence of the difference, or of 1 part in 500,000,000,000, was 

 distinctly detected. 



" Magnetic Qualities of Nickel." (Supplementary Paper.) 

 By J. A. Ewing, F.R.S., Professor of Engineering in University 

 College, Dundee. 



The paper is a supplement to one with the same title by Prof. 

 Ewing and Mr. G. C. Cowan, which was read at a recent meet- 

 ing of the Society. It describes experiments, conducted under 

 the author's direction by two of his students, Mr. W. Low and 

 Mr. D. Low, on the effects of longitudinal compression on the 

 magnetic permeability and retentiveness of nickel. The results 

 are exhibited by means of curves, showing the relation which 

 was determined between the intensity of magnetisation of the 

 metal and the magnetising force, when a nickel bar, reduced to 

 approximate endlessness by a massive iron yoke which formed a 

 magnetic connexion between its ends, was magnetised under 

 more or less stress of longitudinal compression. Corresponding 

 curves show the relation of residual magnetism to magnetising 

 force, for various amounts of stress ; and others are drawn to 

 show the relation of magnetic permeability to magnetic induction. 

 Initial values of the permeability, under very feeble magnetising 

 forces, were also determined. The experiments were concluded 

 by an examination of the behaviour of nickel in magnetic fields 

 •of great strength. Magnetising forces ranging from 3000 to 

 13,000 C.G. S. units were applied by placing a short bobbin with 

 a narrow neck made of nickel between the poles of a large 

 electromagnet, and it was found that these produced a practical 

 •constant intensity of magnetisation which is to be accepted as 

 the saturation value. 



Paris. 



Astronomical Society, June 6. — M. Flammarion, Presi- 

 dent, in the chair. — Various drawings and observations were 

 sent by MM. Petit, Rengel, and G. Vallet. — M. Flammarion read 

 a paper on the solar eclipses of the 19th century, shewing strong 

 discrepancies between M. Oppolzer's charts and the results of 

 observation. Replying to M. Oppert, M. Flammarion said he 

 should not advise historians to base their investigations on those 

 • charts. — M. M. Cornillon sent drawings of a large sunspot from 

 May n to 23. M. Schmoll said that this spot was just on the 

 limits of visibility to the naked eye from May 16 to 18. — M. 

 Gaudibert sent a drawing of the lunar crater Flammarion. A 

 fine rill traverses this crater, and extends to Reaumur after being 

 interrupted by some hills. — M. Schmoll related an observation 

 of the lunar crescent on May 12, the moon being 42J hours old. 

 Its breadth was from 30'' to 35". — M. Trouvelot presented to 

 the Society a series of celestial photographs offered by Prof. 

 Pickering, of Harvard College. The photograph of the Pleiades 

 is specially interesting, and shows the straight trails of nebulous 

 matter which form such a striking feature in the last negatives 

 obtained by MM. Henry. — Thanks were returned to Prof. 

 Pickering, who was unanimously named honorary member of the > 



Society on the proposition of M. Trouvelot and Colonel 

 Laussedat. — Colonel Laussedat explained his method of com- 

 puting solar eclipses graphically, which is two or three times 

 more rapid than the usual numerical calculation. 



Amsterdam. 

 Royal Academy of Sciences, June 30. — M. Beyerinck 

 stated the results he has obtained from experiments on hybrid- 

 ism or crossings with common barley {Hordeum vidgare, H) 

 hexastichon, H. distichon, II. Zeocriton, and H. trifurcatum. 

 made by him since 1884 on a large scale, and illustrated his 

 subject with specimens, some dried and others preserved in 

 spirits. He described the precautions to be taken in such 

 crossing experiments, and deduced the following conclusions : — 

 (1) All the above-mentioned sorts of barley may be crossed 

 with facility, indiscriminately. (2) The hybrids thus obtained 

 are very perfectly self-fertile ; those produced from H. vidgare 

 (fern.) and //. distichon (m.), and those from H. vidgare (fern.) 

 and H. Zeocriton (m.) even cleistogamous. (3) The hybrids of 

 the first generation partake in general of a middle shape between 

 the two parents. An exception to this rule was made by those 

 of H. nudum (fern.) and H. trifurcatum (m.), a great part of 

 which proved to belong to the not expected common inter- 

 mediate form between H. vulgare and H. distichon. A few 

 specimens belonged to the expected cor nut um form. (4) The 

 seedlings from hybrids obtained by self-fertilization are very 

 various. The speaker obtained, besides a few already known 

 ones, some quite new varieties. It was remarkable that the 

 third generation of a cross between H. vulgare (fern.) and 

 H. Zeocriton (m. ) produced H. hexastichon. (5) In the present 

 summer, a cross effected in 1884 between//, distichon (fem. ) 

 and H. trifurcatum (m.) produced a form almost completely 

 without awns. — M. Fiirbringer imparted the results of a research 

 made by M. J. F. van Bemmelen into the origin of the fore- 

 limbs and of the lingual muscles in reptiles. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Electric Lighting ; Its Present Position and Future Prospects : Hammond 

 and Co. (Whitehead, Morris, and Liwe). — A System for the Construction of 

 Crystal Models on the Type of an Ordinary Pla.t : John Gorham (Spon). — 

 An Introduction to the Science and Practice of Photography : Chapman 

 Jones (Iliffe and Sons). — Religion and Science : W. Fitzgerald (Hodges. 

 Figgis, and Co.). — A Practical Decimal System for Great Britain and her 

 Colonies : R. T. Rohde (E. Wilson). — The Rothamsted Experiments on the 

 Growth of Wheat, Barley, and the Mixed Herbage of Grass Land : Prof. 

 W. Fream (Horace Cox). — Rock-Forming Minerals: Frank Rutley (T. 

 Murby). — Smithsonian Report, 1885, Part 2 (Washington. U.S.)— The 

 Glasgow and West of Scotland Technical Col'ege Calendar, i883. 



CONTENTS. pace 



Lord Armstrong on Technical Education 313 



Explorations and Adventures in New Guinea . . . 315 



Mine-Surveying. By C. Le Neve Foster 317 



Our Book Shelf :— 



Smart : " Charles A. Gillig's Tours and Excursions in 



Great Britain" 318 



Letters to the Editor : — 



The Supply of Bait for Sea-Fishermen. — G.C. Bourne 318 

 Geometric Meaning of Differential Equations. — 



Lieut.-Colonel Allan Cunningham, R.E. . . 318 

 British Earthworms. — Dr. Wm. B. Benham . . . 319 

 The Sun Motor. {Illustrated.) By Major John 



Ericsson 319 



The White Race of Palestine. By Prof. A. H. Sayce 321 

 Engineering Schools. By Prof. George Francis 



Fitzgerald, F.R.S 322 



The Gape Worm of Fowls (Syngamvs trachealis). By 



Lord Walsingham, F.R.S. 324 



Notes 325 



Our Astronomical Co'.umn : — 



Variable Stars 328 



Gomet 1888 a (Sawerthal) 32S 



Astronomical Phenomena for the Week 1888 



August 5-11 328 



On Partial Impregnation. By Prof. A. Weismann 



and C. Ischikawa 329 



How to increase the Produce of the Soil. By Prof. 



John Wrightson 330 



The Burial Customs of the Ainos. By Rev. J. 



Bachelor 331 



University and Educational Intelligence 331 



Societies and Academies 331 



Books, Pamphlets, and Serials Received . . . . • 336 



