4AO 



JVA TURE 



(September 3, 1908 



(5) 'i'hc existing tlieory of condensation on ionic nuclei 

 has been given, values of S have been calculated from it, 

 and compared with S deduced from the observed expansions. 

 The agreement in the case of acetic, propionic, n-butyric, 

 and iso-butyric acids, and methyl alcohol is very close. 



(6) The expansion and supersaturation necessary for con- 

 densation on the natural nuclei have been determined for 

 the same (dust-free) vapours. In the case of formic, acetic, 

 and butyric acids a distinctly greater expansion is required 

 to catch the natural nuclei than that required for the ionic 

 nuclei produced by Rontgen rays. 



(7) As the expansion was increased the number of drops 

 usually increased continuously with it, so that the fog 

 point was ill-defined, except in the case of tertiary amyl 

 alcohol. 



(8) Ethyl acetate, methyl butyrate, propyl acetate, acetic 

 acid, and iso-amyl alcohol were found to condense for a 

 smaller expansion on the positive nucleus than on the 

 negative. Water is the only known suhstance for which 

 the negative ionic nucleus is more efficient than the 

 positive. 



(g) On bubbling air through methyl, ethyl, and iso- 

 amyl alcohols, ethyl acetate, propyl acetate, methyl 

 butyrate, chloroform, and ethyl iodide they became nega- 

 tively electrified. This was the sign of the electrification 

 to be expected from Prof. Thomson's double layer theory 

 of the relative efficiency of ionic nuclei. Acetic acid was 

 not in agreement with the theory, for it became positively 

 charged on bubbling. 



Paris. 



Academy of Sciences, Aucu't 24. — M. Bouquet He la 

 Grve in the chair. — A problem relating to the theory of 

 orthogonal systems and to the method of the mobile 

 trihedron : Gaston Darboux. — Methylation in the ethylene 

 series from the point of view of volatility : Louis Henry. 

 The replacement of the hydrogen atoms attached to carbon 

 in ethylene glycol by the methyl group causes a lowering 

 of the boiling point, although the replacement of the 

 hydrogen atoms in ethylene has the contrary effect. This 

 is probably due to the association of the molecules in the 

 alcohols, the coefficient of association becoming less as 

 the number of hydrogen atoms substituted is increased. 

 The boiling point is raised when methyl groups are intro- 

 duced into ethylene chloride, and the ethylene oxides behave 

 in a similar manner. — Twilight illuminations ; Ernest 

 Esclangron. A discussion of the colour effects observed at 

 Bordeaux during twilight, the causes of which still remain 

 unexplained. — Observations of the sun made at the Observa- 

 tory of Lyons during the second quarter of 1908 : J. 

 Guillaume. Observations were made on sixty-five days, 

 and tables are given showing the number of spots, their 

 distribution in latitude, and the distribution of the faculjE 

 in latitude. — The theory of asymptotic lines : A. 

 Demoulin. — The zeros of the integrals of a class of 

 differential equations : Georges Remoundos. — The varia- 

 tion of two ruled surfaces : M. Haag. — Liquid helium : 

 H. Kammerlingh Onnes. Details are given of the methods 

 adopted for the liquefaction of 200 litres of helium on 

 July 10. This experiment required the use of 7.5 litres of 

 liquid air and 20 litres of liquid hydrogen. Owing to the 

 extremely small c.-ipillarity of liquid helium, the surface of 

 the liquid meets the side of the containing vessel like a 

 knife blade, and the formation of the first quantity of 

 liquid escaped observation. The helium remained in the 

 liquid state for two hours ; its density was 0-154, and its 

 boiling point, determined with a helium thermometer, 4°'3. 

 The critical temperature is probably about 5°, and the 

 critical pressure not much above 2-3 atmospheres. The 

 helium was not solidified when the pressure was reduced 

 to less than 10 mm. of mercm-v. — The action of chloride 

 of arsenic on cobalt : F. Ducelliez. This reaction gives 

 rise to cobalt chloride, together with an arsenide of cobalt. 

 At a temper.ature of iooo° C. Co^.^s, is formed, at 600° C. 

 to 800° C. CoAs, at about 4.';o° C. the product is Co. As; : 

 below 400° C. CoAs, is slowly formed. — The action of 

 arsenic trichloride upon nickel and arseno-nickels : Em. 

 Vig^OMroux. The arsenides Ni..'\s.,, Ni.^s. and Ni.As,. were 

 obtained by varying the conditions of the experiment. — 



NO. 2027, VOL. 78] 



The two methods of preparation of monomethylamine : 

 Maurice Francois. In a previous paper the author has 

 described a method of separating methylamine from small 

 proportions of ammonia by means of yellow mercuric oxide. 

 To prepare the pure amine by this process it is requisite 

 that ammoni.i should be the sole impurity, and the present 

 paper gives a comparative study of the methods of Hoff- 

 mann (bromine and acetamide) and Brochet and Cambier 

 (ammonium chloride and formaldehyde) from this point of 

 view. The methylamine hydrochloride prepared by the 

 latter method proved to be very impure ; but the product 

 of Hoffmann's reaction was quite suitable for further 

 purification by mercuric oxide. — The mode of growth of 

 the Morillo {Morchella semilibera) : Louis Matruchot. — 

 The influences of the external conditions on the develop- 

 ment and sexuality of the prothallus of Polyprodiacere : G. 

 Peri-in. — Physiological study on the development of fruits 

 and seeds : W. Lubimenko. Perforation of the pericarp 

 causes an atmosphere with a lower percentage of carbon 

 dioxide to surround the ovule, resulting in arrested devclo]5- 

 ment. — .\ disease of the oak : MM. Griffon and 

 Maublance. This disease, which since the spring has 

 attacked the oaks in a great part of France, is due to a 

 white mould of the genus Oidium. It spreads rapidly, 

 and has caused great damage. — The minute structure of 

 the sporozoites of Plasmodium reliclum : Edmond Sergent 

 r\ud Htienne Sergent. 



CONTENTS. PAGF 



Marine Deposits 409 



The Contrast between German and English Educa- 

 tion. By Prof. M. E. Sadler 410 



Our Book Shelf:— 



Edgcumbe : "Industrial Electrical Measuring Instru- 

 ments." — L. C 411 



Deinhardt and Schlomann : "The Deinhardt-Schlo- 

 mann .Series of Technical Dictionaries in Six Lan- 

 guages, ('•erman. English, French, Russian, Italian, 



Spanish," Vol. iii 4:2 



Ka^sner : " Das Wetter und seine Bedeutung fiir das 



praktische Leben " 412 



Letters to the Editor: — 



Indiscriminate Criiicisni. — Earl of Berkeley, F.R.F. 412 

 The Rotation of a Crystal of Tourmaline by Plane 



Polarised Light. — John A. Anderson 413 



Access to Chemical Works. — Chemist 413 



Fly Fever in Africa. By Sir David Bruce, F.R.S. . 413 



The Late Henri Becquerel 414 



The Dublin Meeting of the British Association. 



By E. E. Fournier . 416 



Inaugural j\ddress by Francis Darwin, M.A., 

 Ph.D., LL.D., F.R.S., President of the 



Association 416 



Section A. — Mathematics and Physics. — Opening 

 Address by W. N. Shaw, Sc.D., LL.D., F.R.S., 



President of the Section 425 



Notes 431 



Our Astronomical Column :— 



Astronomical Occurrences in September 435 



Observation of Phcebe, Saturn's Ninth Satellite . . . 435 



The Parallax of 61 Cygni 435 



Prominences at the Sun's Poles 435 



Observaiions of Variible Stars .... 436 



The Influence of the Earth's Rotation on the Courses 



of Rivers . 436 



A Possibly Undiscovered Form of Solar Radiation . 436 

 Welsh Astronomical Traditions. By Rev. John 



Griffith 436 



The Prague Exhibition. By T. LI. H 437 



The Improvement of Agricultural Plants 43S 



University and Educational Intelligence 439 



Societies and Academies 439 



