34© 



NATURE 



[December 26, 1918 



bottle if the glass of which it was made was unsuit- 

 able for contact with the material it was intended to 

 hold. Medical bottles in particular should be sub- 

 d to tests in order to ascertain that they con- 

 formed to a certain standard. One test was sug- 

 gested in which solutions of the alkaloids and mer- 

 cury solutions were kept in contact with the bottle 

 twenty-four hours and the absence or production of 

 a sediment noted. The results of heating a number of 

 dill. icnt types of bottle in contact with water and 

 steam under pressure were also described and tabu- 

 lated, and emphasis was laid on the necessity for 

 avoiding excessive use of soda-ash in melts. In the 

 case of bottles made from sand, soda-ash, and linn- 

 spar, it was pointed oul thai lime spar should not 

 fall below 7 to S per cent, of the batch mixture, other- 

 wise the glass was acted on by water to a marked 

 extent. The author also dealt with the problem of 

 workability, win the,- from the point of view of band- 

 working or machine-working. The effect of different 

 constituents present in bottle-glass, such as silica, 

 soda-ash, lime, magnesia, and alumina, was described, 

 and the importance of arranging a batch so that the 

 resulting glass should sel quickly was emphasised, if 

 production at a rapid rate was desired. The limits of 

 workability for glasses containing sand and soda, with 

 lime, magnesia, or alumina, were set out. 



Dublin. , 



Royal Dublin Society, November 19.— Dr. G. H. 

 Pethybridge in the chair.— Dr. G. H. Pethybridge and 

 H. A. Laffertv ; .\ disease of tomato and other plants 

 caused by a new species of Phvtophthora. The disease 

 is one in which the root system and base of the stem 

 of young plants become involved in a iot leading to 

 the death of the plants. It is caused by a species of 

 Phvtophthora hitherto undescribed, having sexual 

 organs (with amphigynal antheridia) similar to those 

 first described for V. erythroseptica. The disease is 

 contracted from the soil, and also occurs naturally in 

 Petunias. The fungus was proved to be parasitic also 

 towards Aster, Gilia, Cheiranthus, Solarium tubero- 

 sum, Fagus, etc., and it is extremely probable that 

 it occurs naturally and causes disease in some of 

 these plants. Owing to the facility with which the 

 tomato produces adventitious roots, affected plants 

 can not infrequently be "cured" bv amputating the 

 diseased parts and treating the still healthy portions 

 as cuttings. The disease causes serious losses in nur- 

 series, but can be avoided by raising seedlings in 

 steam-sterilised compost. — E. j. Sheeny : Part i., An 

 economical method of determining the average per- 

 centage of fat in a cow's milk for a lactation period. 

 An account of two experiments conducted at the Albert 

 Agricultural College. The author explains the liability 

 to error in determining the average percentage of fat 

 in a cow's milk by the method of averaging two or 

 three random samples taken during the lactation 

 period, because of the great variability in fat yields 

 fur successive days. A test is suggested over' four 

 cutive days as suitable and convenient, and this 

 single test is applied to the fifth month of the lacta- 

 tion period as a means of determining the avei < 

 percentage for the whole period. Part'ii., The com- 

 parative Variation in the different constituents of cow's 

 milk. ^ In this part an analysis is made of the 

 variability of milk, and it is shown by graphical repn 

 sentation that the ,,ii,], n0 | f al an( j W ater in the 

 milk of successive days vary approximately as 

 the milk, while fat varies in a fashion peculiar to 

 itself, suggesting that th ion of fat is governed 



bv factors not identical with thosi govi rning tin- secre- 

 tion of the other constituents. 

 NO. 2565, VOL. I02] 



BOOKS RECEIVED. 



Catalogue of the Scientific Serial Publications in the 

 Principal Libraries of Calcutta. Compiled for the 

 Asiatic Society of Bengal by S. Kemp. Pp. xii+ 

 292. (Calcutta : Asiatic Society of Bengal.) 



The Cambridge University Calendar for the Year 

 [918 [9. Pp. xxvi+1074. (Cambridge: At the Uni- 

 versity Press.) 105. bd. net. 



Who Giveth Us the Victory. Bv A. Mee. Pp. 191. 

 (London: George Allen and Unwin, Ltd.) e$. net. 



Hcho Personalities. By F. Watts. Pp. in. 

 (London : George Allen and Unwin, Ltd.) 44. 6d. 

 net. 



Ambulance de "l'Oce^an," La Panne. | 

 Fasi . i. Pp. 376. il'ai i- : Mas,,, 11 et I 'ie.) , 

 i;er 



Everyman's Chemistry. By E. Hendrick. Pp. x + 

 319. (London : University of London Press, Ltd.) 

 8s. 6d. net. 



Coniferous Trees for Profit and Ornament. Bv 

 A. D. Webster. Pp. \\ 298. (London: Constable 

 and ( !o., Ltd.) 21S. net. 



The Scientist's Reference Book and Diary, 1919. 

 (Manchester: J. Woollev, Sons, and Co., Ltd.) 



The Production and Treatment of Vegetable Oils. 

 By T. W. Chalmers. Pp. x+ 152 + 9 folding plates. 

 (London : Constable and Co., Ltd.) 21s. net. 



Agricultural Bacteriologv. By Prof. H. W. Conn. 

 Third edition, revised bv H. J. Conn. Pp. x + 357. 

 (Philadelphia : P. Blakiston's Son and Co.) 2 dollars 

 net. 



CONTENTS. page 



Mycology and Plant Pathology. By E. S. S. . . . 321 



Dynamical and Popular Astronomy. By H. J. 322 



Electrical Instruments. By Dr. A. Russell . . . 323 



Our Bookshelf 323 



Letters to the Editor:— 



Fuel Economises. — Dr. J. A. Harker, F.R.S. ; 



Hon. R. C. Parsons . . 324 



The Perception of Sound. — Prof. W. M. Bayliss, 



F-R.S 3*5 



1 he Meteoric Shower of December. — W. F. Denning 325 

 Lady Roberts's Field Glass Fund. — Countess Roberts 325 

 Inter-allied Conference on International Organisa- 

 tions in Science. By C. G. K. 325 



Our Roads .... . . 327 



The American Chemist in Warfare. Bv Sir T. E. 



Thorpe, C.B., F.R.S . . .328 



Notes 330 



Our Astronomical Column : — 



The Planet Mercury 334 



The January Meteors 334 



Opposition of Vesta . . . • 334 



Distribution of Luminosity in Star Clusters ... . 334 

 Prize Awards of the Paris Academy of Sciences for 



1918 334 



A New Theory of the Ice Age. By W. W. B. . . 335 



Report of the Development Commissioners .... 336 



University and Educational Intelligence . ... 337 



Societies and Academies 338 



Books Received 340 



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