642 



NATURE 



[February 12, 1920 



for chemical laboratory use was entirely imported. 1 

 Our own glass manufacturers have risen to the occa- \ 

 sion, and it is to be desired that they should in the 

 future be able to retain a position in the industry. 



It has been known for many years that by treating 

 a photographic plate with a weak solution of a soluble 

 iodide development may be accelerated. In the 

 January issue of the Journal of the Royal Photo- 

 graphic Society S. E. Sheppard and G. Meyer (of 

 the Eastman Kodak Co.) describe some results of their 

 investigations of this action. It seems that the iodide . 

 has little or no effect on the action of developers that 

 produce a visible result very soon after their applica- 

 tion, but that developers like glycin and h\-droquinone, 

 which are slow to produce a visible effect, are much 

 accelerated by it in the early stages of development. 

 With hydroquinone the whole course of development 

 is changed. Ferrous oxalate is not affected by it. 

 The authors suggest that the process of development 

 takes place by the formation of a complex of silver 

 haloid and developer (which then breaks up into 

 metallic silver and oxidation products of the developer), 

 and that the small proportion of silver iodide pro- 

 duced facilitates the formation of this complex. It is 

 well established that silver iodide has a far stronger 

 mordanting action on dyes than silver bromide. Un- 

 fortunately for the practical application of the process, 

 the iodide treatment seems always to produce fog. 



The Journal of the British Science Guild for 

 January contains an appeal to members to co-operate 

 more fully in the work of the journal, which is 

 extending its scope. A feature of interest in the 

 present issue of the journal is the series of short 

 editorial notes on topical events, forming a useful 

 supplement to the more detailed accounts of reports, 

 etc., following. A short account is given of the last 

 British Scientific Products Exhibition, and Sir Richard 

 Gregory's address on "Science in Industry," delivered 

 before the Circle of Scientific, Technical, and , Trade 

 Journalists at its meeting on the opening day of 

 the exhibition, is reproduced. The report of the 

 Microscope Committee, originally published in the 

 Journal in 1916, is now presented in its revised form. 

 The newly formed Parliamentary Committee, in con- 

 junction with the Agricultural Committee, was instru- 

 mental in presenting a memorandum on the Forestry 

 .Act, stress being laid on the inclusion, amongst the 

 seven suggested Commissioners, of at least one 

 member having adequate technical and scientific 

 knowledge of the subject. In view of the con- 

 templated legislative measures in regard to deep-sea 

 fisheries, the need for a comprehensive scientific 

 survey of the industry, in order that knowledge may 

 precede legislation, is again pointed out. 



The President of the Board of Education, we note 

 in the Journal of the British Science Guild for January, 

 does not see his way to adopt at once the suggestion 

 of the guild for a consultative committee to advise 

 the Board on matters affecting the relationship of 

 universities and higher technical education to industry, 

 but offers hope that the request may be complied with 

 later. The suggestion conveyed to the Foreign Office 

 NO. 2624, VOL. 104] 



that scientific attaches should be added to British* 

 Embassies and Legations was met by the counter- 

 proposal that technical associations should make their 

 own arrangements to obtain information on foreign ! 

 developments. The Department of Overseas Trade 

 has issued a circular requesting early intimation of 

 visits to foreign countries by representatives of British 

 firms, in order that consular officers and other officers 

 abroad may be notified. In view of the extensive and 

 valuable work recorded, the appeal being made by 

 the guild for new members and additional funds 

 should meet with generous response. The address of 

 the guild is now 6 John Street, Adelphi, W.C.2. 



The Cammellaird-Fullagar marine oil-engine, con- 

 structed by Messrs. Cammell Laird and Co., of 

 Birkenhead, forms the subject of an illustrated article 

 in Engineering for January 30. This engine is of 

 the two-cycle type, with tv-JO opposed pistons working 

 in the same cylinder, which is open at both ends, and 

 the cycle takes place between the pistons. There are 

 two vertical cylinders in each unit, arranged side by 

 side, and two cranks at 180°. The top piston in each 

 cylinder is connected by inclined rods to the bottom 

 piston of the other cylinder. There are great ad\an- 

 tages in this arrangement, among which may be men- 

 tioned the saving in space, which is reduced greatly 

 as compared with an ordinary marine four-cycle 

 engine. The opposed piston type has been tried for 

 steam, gas, and petrol engines, and has so far been 

 found wanting. For oil-engines it has several attrac- 

 tive features. There is no cylinder head, and the liner 

 is a single tube free to expand at both ends. 

 Scavenging is simple and effective, since the sweeping- 

 out air enters at the end opposite to that through 

 which the exhaust leaves, and no valves are required 

 to control the scavenging. The piston speed can, in 

 effect, be doubled, due to the compression taking place 

 between the approaching pistons, and thus reducing 

 the most important heat losses during this stroke of 

 the cycle. The turning moment is improved, and 

 stresses are not taken up by the engine framing, but 

 confined to the moving parts of the engine. The 

 test-bed results for the engine under notice are good, 

 and the performances under seagoing conditions will 

 be watched with the greatest interest. 



The latest catalogue (No. 185) of Messrs. W. Heffer 

 and Sons, Ltd., Cambridge, contains the titles of 

 nearlv two thousand works, ranging over the subjects 

 of agriculture and husbandry, anthropology and 

 ethnology, botany, chemistry, geology, mineralogy and 

 palaeontology, biology, physiology, anatomy and medi- 

 cine, mathematics and physics, astronomy, and en- 

 gineering. Some of the volumes were formerly the 

 property of Sir William Crookes and Sir Frank Crisp. 

 In addition to the books referred to, there are for 

 disposal a number of portraits of scientific men. 



OUR ASTRONOMICAL COLUMN. 

 Large Fireball on February 4.— In the early 

 evening at 6h. 14m. a splendid meteor was seen from 

 various parts of the country. Among the observers 

 were several persons who have gained experience in 

 recording meteors, so that the real path derived from 



