February 5, 1920] 



NATURE 



611 



speakers emphasised the need for a systematic com- 

 parison of the various existing units and the estab- 

 lishment, if possible, of a standard of so-called 

 "white" light. 



Whilst the chemistry of gelatin has been inves- 

 tigated with much care, less attention has been given 

 to that of glue. Both gelatin and glue are hydrolytic 

 products of the collagen present in hides, but they 

 represent different phases of the hydrolysis, and the 

 details of the manufacture of glue have largely been 

 kept secret. Crucial points are, first, the stage at 

 which the process of hydrolysis must be stopped and 

 the degree of concentration necessary in order to 

 obtain a glue solution which will "set" to a jelly; 

 and next, the method of drying this jelly into the 

 finished glue. A low temperature has been considered 

 necessary for successful drying, and also for avoiding 

 bacterial action during the process. Hence the making 

 of glue in warm countries, such as India, has hitherto 

 not been found practicable. \ paper by Mr. K. C. 

 Srinivasan, of the Department of Industries, Madras 

 ("The Manufacture of Glue in the Tropics"), describes 

 how the foregoing points have been investigated by 

 the Department, and the difficulties overcome. It is 

 claimed that by a study of the chemical principles 

 involved, and by laboratory and factory experiments, 

 the details of manufacture have been successfully 

 adapted to the climatic conditions prevailing even in 

 the hottest parts of India. 



Mr. D. Brownlie gives some further exact data 

 on the running of steam-boiler plants in Engineering 

 for January 16. The subject dealt with is that of 

 steam jets under or over the fire-bars, and out of the 

 250 typical steam-boiler plants examined no fewer than 

 93 plants, or 37 per cent., were fitted with steam jets. 

 The makers of the various types of furnaces so fitted 

 confess, as a rule, to a modest i to 3 per cent, of 

 the steam production being used in the jets. Mr. 

 Brownlie finds that the average steam consumption 

 for the 93 plants is 56 per cent, of the total steam 

 produced, and that the figure varied from i to 20 per 

 cent. In the present article the results derived from 

 130 plants are considered, including 437 boilers both 

 hand- and mechanically-fired. The averages are 

 6-6 per cent, for hand-firing and 67 per cent, for 

 mechanical-firing. The lowest figure was 050 per 

 cent., and the highest 21-4 per cent. If a given plant 

 were taken in hand and scientific methods of control 

 adopted, figures like 7J to 15 per cent, of the steam 

 production could be cut down to 3 or 4 per cent, with 

 most types of steam-jet apparatus. Some of the ap- 

 paratus in use is of crude and unscientific design, and 

 incapable of giving good results. Mr. Brownlie 

 estimates that a saving for the whole country of from 

 1,025,000 to 1,345,000 tons of coal per annum could 

 be effected, partly by proper control and partly by 

 getting rid of steam jets working under unsuitable 

 conditions. 



Messrs. H. K. Lewis and Co., Ltd., 136 Gower 

 Street, W.C.i, have just issued a list of secondhand 

 books (many of which are from their circulating 

 library) in medicine and allied subjects which should 

 be seen by all in search of books of this character 

 NO. 2623, VOL. 104] 



at bargain prices. The reductions in many cases are 

 very great. Messrs. Lewis have also sent us a list 

 of the new books and new editions added to their 

 medical and scientific circulating library during the 

 months October to December last. 



Messrs. Cassell and Co., Ltd., promise for February 

 a book of travel by Sir Martin Conway entitled 

 " Mountain Memories : A Pilgrimage of Romance," 

 illustrated by the author. The new list of Messrs. 

 Constable and Co., Ltd., includes "Elementary 

 Mathematics," H. E. J. Curzon ; "Electric Welding 

 and Welding .Appliances," H. Carpmael (Engineer 

 Library); "Paper-making and its Machinery," T. W. 

 Chalmers {Engineer Library) ; " Calculation of Elec- 

 trical Conductors," W. T. Taylor; "Low Grade and 

 Waste Fuels for Power Generation," J. B. C. 

 Kershaw; "Reinforced Concrete Diagrams," J. 

 Williamson; "The Measurement of Steady and 

 Fluctuating Temperatures," R. Royds ; "Heat 

 Transmission," R. Royds; "The Efficiency of Pumps 

 and Ejectors," E. C. Bowden-Smith ; "Oil-Firing 

 for Kitchen Ranges," E. C. Bowden-Smith; "Stor- 

 ing," H. B. Twyford; "Public Health Chemical 

 -Analysis," R. C. Frederick and A. Forster; 

 "Human Psychology," H. C. Warren; "Wild 

 Creatures of Garden and Hedgerow," F. Pitt ; 

 and new editions of "The Propagation of Electric 

 Currents in Telephone and Telegraph Conductors," 

 Prof. J. A. Fleming; "The Theory of Electric Cables 

 and Networks," Dr. A. Russell; and "Ship Form 

 Resistance and Screw Propulsion," G. S. Baker. 



The February list of Messrs. Longmans and Co. 

 contains announcements of many books relating to 

 science and education. Among those not already 

 alluded to in Nature we notice " The Valuation of 

 Mineral Property," Sir R. A. S. Redmayne and G. 

 Stone; "Cement," B. Blount; "Plantation Rubber," 

 G. S. Whitby ; and " Margarine and Butter Substi- 

 tutes," W. Clayton (Monographs on Industrial 

 Chemistry); "The Principles and Designs of Print- 

 ing Telegraph Systems and Mechanisms," H. H. 

 Harrison; "Telephone^ Exchanges: Automatic Equip- 

 ment," B. O. Anson; "Telephone Exchanges: 

 Manual Equipment," H. S. Thompson; "Subscribers' 

 Telephone Equipment," H. S. Thompson; "Over- 

 head Construction," J. W. Atkinson; "Underground 

 Construction," A. O. Gibbon; "Inland Telegraph 

 and Submarine Cable Office Equipment," E. Lack; 

 "Railway Telegraphs," C. W. Slingo; and "Testing 

 of Lines, Apparatus, and Material," F. L. Henley 

 (Manuals of Telegraph and Telephone Engineering); 

 "Applied Naval Architecture," W. J. Lovett; "In- 

 dustrial Administration," a series of lectures by B. S. 

 Rowntree, T. H. Pear, A. E. Berriman, Dr. J. M. 

 Legge, Prof. L. Hill, T. B. Johnstone, and St. George 

 Heath; "Forage Crops in Denmark," H. Faber; 

 "The Fireman's Handbook and Guide to Fuel 

 Economy," C. F. Wade; ".An Essay on Mediaval 

 Economic Teaching," G. O'Brien; and a new edition, 

 in two parts, of " Optical Projection : A Treatise on 

 the Use of the Lantern in Exhibition and Scientific 

 Demonstration," Lewis Wright, rewritten by his son, 

 R. S. Wright, part J, illustrated. 



