February 13, 1919] 



NATURE 



47' 



Light-filters made of .1 new yellow dye have just 

 introduced b) h. Eastman Kodak Co. Picric 

 i< ill being too unstable (filters made with it turn 

 brown), and a more sharp! rption being 



sometimes desirable than tint given by "filter yellow," 

 Messrs. Mees and Clarke sought for .1 dye that would 

 fulfil the desired conditions. The) found that glucose- 

 phenylosazone gives almost as good absorption of the 

 ultra-violel .1- filtei yellow," as well as .1 sharper cut 

 on tlii othi 1 sid< of the band, and is satisfactorily stable 

 The actual derivative used, the osazone itself being in- 

 soluble in water, is the sodium salt of glucosephenyl- 

 1 id, and fnr inn'. enienc e the) 

 call it "Eastman yellow." The tiltrrs are made of 

 three densities, one special!) foi aerial photography, 

 and this has been adopted by the American forces. 

 Further details with ab irves are given in 



the British Journal of Photography for January 31. 



An article on metric measurements appears in the 

 January issue of Cheap Steam, a periodical issued b) 

 the well-known engineers, Messrs. Ed. Bennis and 

 Co., Ltd. From the point of view of the writer ol 

 article, the greatest advantage to be derived from 

 the adoption of the mi hi 1 nabling of 



manufacturers to competi on more equal terms with 



11 rivals in the world's markets. Inability or 

 unwillingness of the British manufacturer to estimate 

 for overseas clients in terms which they understand 



iSl main a contract to this country. One secret 



rmany's rapid progress as .1 foreign trader was 

 the promptitude with which she adapted her business 

 methods to the habits and customs of the various 

 nations with which sh< was anxious to deal, and she 



annoyed and puzzled possible customers abroad 



by quoting quantities and prici - in terms which they 



<lid not understand. In 1864 an Act was passed to 



missive the use of the metric system; in 



massed making the. use of the 



n optional. ["he time is now ripe for making ; 

 it compul 



Buei 1 the state of the atmosphere on 



of the sea has been verj variously estimated, 

 particularly a> regards the relative importance of 

 barometrii pressure and wind. At one of the recent 

 British Association geophysical discussions Col. Sir 

 C. F. Close reviewed the subject, and described cer- 

 tain new dal by th< Ordnance Survey 

 Journal, July, [918). These showed 

 that at the observation points chosen, on the coast 

 of the Atlantic Ocean and the North Sea, the sea- 

 li . 1 responds almost immediatel) to barometric varia- 

 tions. \ rise or fall in the height of the mercury is 

 ed with a fall or rise of sea-level of 13-5 times 



unt (equivalent to the variation in a water- 

 barometer) Changes of level due to winds cause 

 some fluctuation in individual estimates of the ratio 

 (from 7 to 20, roughly), but not sufficiently to mask 



■ connection between sea-level and barometric 

 pr< ssure. In a narrow, land-locked sea, however, it 

 might be expected that the wind would have relatively 



influence, and this is confirmed by a recent 

 stud) of the Baltic sea. level by Rolf Witting (O/v. aj 

 Finska Vet.Soc. Forh., vol. lix., A, 13, Helsingfors, 



lb. punly hydrostatic effect of a gradient of I 

 barometric pressure over any region is to produce an 

 ;ite slope of the sea-surface. But such a distribu- 

 tion of atmospheric pressure is usually accompanied 

 by winds directed along the isobars, with the higher 



ire on the I. ft tin the northern hemispher< 

 This tends to heap up the waters with a gradient 

 perpendiculai to the formei one, and in the Baltic 

 this slope appears to be about t-8 times as great as ' 

 the hydrostatic slope. The resultant gradient is rather 



NO. 2572, VOL. I02] 



more than twice the latter, and is inclined to it in 

 azimuth at about 55 . 



The largest plate-rolling mill in the world is 

 described in an illustrated article in Engineering for 

 iry 24. This mill belongs to the Lukens Steel 

 Co., of Coatesville, Pennsylvania. It is a four-high 

 reversing type mill, 17 ft. wide on the rolls, and is 

 capable of rolling plates up to 16 ft. in width, and 

 circular plates a few inches wider. It is built on the 

 principle of the two-high reversing plate-stand used 

 in the British Isles, with the modification that the 

 two finishing rolls are backed by two large supporting 

 rolls. The latter rolls stiffen the mill and prevent 

 springing of the operating rolls when rolling wide, thin 

 plates, thus ensuring uniform thickness in the finished 

 product. There are two 34 in. diameter by 204 in. 

 working-face operating rolls of chilled iron with 27-in. 

 necks, weighing about thirty tons each, and two 

 30 in. diameter backing rolls of cast-steel with 36-in. 

 necks, weighing about sixty tons each. The mill 

 stands about 40 ft. from the top of the screw-cover 

 to the bottom of the shoes. The screw-down rig 

 is of the well-known worm and worm-wheel design, 

 and is driven by two 150-h.p. motors, one on each 

 housing. The mill is driven by a twin tandem com- 

 pound engine, having cylinders of 46 in. and 70 in. 

 diameter by 60 in. stroke, and is fitted with a jack- 

 shaft and a gear ratio of one to two, which renders it 

 capable of giving an enormous torque. Mechanical 

 tables are provided so arranged as to do away with 

 hand-labour wherever possible. 



Messrs. Longman's and Co.'s new list of annoum 1 - 

 ments contains many books of scientific interest, some 

 of which have already been referred to in thesi 

 columns. Others arc: "Applied Aero-dynamics,' 

 L. Bairstow, illustrated; "Aeroplane Structures," 

 A. J. S. Pippard and Capt. L. Pritchard, with a pre- 

 face by L. Bairstow, illustrated; "Corrosion and 

 Decay of Metals," Prof. C. H. Desch ; " Lead and its 

 Compounds," Dr. J. A. Stnvthe; "Boiler Chemistry," 

 J. II. Paul; "The Rare "Earth Metals," Dr. J. "F. 

 Spencer; "Chemical Affinity and Chemical Equili- 

 brium," Dr. II. S. Taylor; a new edition of "Osmotic 

 Pressure," Prof. A. Findlay; "Ships' Boats: Their 

 Qualities, Construction, Equipment, and Launching 

 Appliances," E. YV. Blocksidge; and "Efficient Boiler 

 Managi ment, with Notes on the Firing of Coal-fired 

 Reheating Furnaces," C. F. Wade. Messrs. Long- 

 mans also have in hand the third edition of " British 

 Birds," A. Thorburn, illustrated, the first two volumes 

 of which have been published. Vol. iii. is promised 

 for March, and vol. iv. for April. 



Mr. F. Edwards, 83 High Street, Marylebone, W.i, 

 has just published Catalogue No. 386 of books, manu- 

 scripts, and engravings relating to India and Ceylon. 

 1 1 contains many rare works and a number of books 

 ..I scientific interest, e.g. a complete set of the "Cata- 

 logue of the Birds in the British Museum," 27 vols.; 

 Hooker's "Illustrations of Himalayan Plants"; Capt. 

 W. V. Legge's "History of the Birds of Ceylon": 

 and vols. i. to v. of Moore's " Lepidoptera Indica." 

 Mr. Edwards has also for disposal the Sanskrit libran 

 of tin late Col. G. A. Jacob, comprising about 700 vols. 



Messrs. Dulau and Co., Ltd., have just 

 from their new address (34 Margaret Street, Cavendish 

 Square, W.i) Catalogue No. 74 of some 1200 books 

 on botany, agriculture, and zoology which theyhave 

 fur disposal. It gives particulars of many rare editions 

 uf works dealing with the subjects referred to, ami 

 should be of service to many readers of NATURE. \ 

 feature of the catalogue is many of the earlier volumes 

 of the British Museum Zoological Catalogues and 



I.istS. 



