January io, 191 8] 



NATURE. 



375 



jection machine, which throws on a screen a shadow- 

 like image of the screw thread, magnified a definite 

 number of times. This image is then superposed on a 

 diagram of the correct thread form, drawn to the same 

 magnification. Thus variations from the true form 

 can be seen and measured with a scale. A simple pro- 

 jection apparatus and another having a large field of 

 view are described, together with some convenient 

 accessories. 



With the exception of core diameter and pitch, the 

 elements of a screw ring gauge cannot be measured 

 readily. The method of taking plaster casts has been 

 tried, but such casts cannot at present be relied upon 



• to nearer than ±00005 to ±ooor in. In general, 

 screw ring gauges are not measured, but tested 

 between limits by "go" and "not go" check plugs, 

 made so as to test each diameter independently. 



The pamphlet is written in a very practical manner, 

 and sufficient information and drawings are given to 

 enable anyone interested to set up the various appli- 

 ances for himself. We are also glad to note that 

 manufacturers who contemplate the installation of 

 measuring instruments, or have experienced difficulties 

 in measurement, are invited to visit the laboratory by 

 appointment to discuss their particular problems with 

 the members of the staff. 



MARINE BIOLOGY. 



THE twenty-fourth report (1916) of the Danish Bio- 

 logical Station contains two papers of much in- 

 terest to marine biologists. Dr. C. G. J. Petersen 

 gives a useful account of the development of the ex- 



• ternal characters in three of the common species of 

 Gobius. The great difficulty there is in discriminating 

 between the young stages of these fishes is well known 

 to those who have handled general collections made in 

 European waters, and Dr. Petersen's careful descrip- 



. tions will be much appreciated. The second paper in 

 the report is by Dr. H. Blegvad, on the food of fishes 

 in Danish waters within the Skaw. The new feature 

 in this work is that, in addition to an account of the 

 kind of food upon which each species was found to be 

 feeding, the weight of each kind of food found in the 

 fish and the weight of the fish itself were recorded. 

 In this way a more accurate idea of the relative im- 

 portance of the different kinds of food can be obtained. 

 In the Marine Biological Report, No. iii., 1916, for 

 the province of the Cape of Good Hope, Dr. J. D. F. 

 Gilchrist, in the first paper, describes the eggs and 

 larvae of a number of Cape fishes. Unfortunately the 

 figures which accompany this paper appear to have lost 

 a great deal in the reproduction, and many of them can 

 scarcely be considered adequate for recognising these 

 very delicate forms, the identification of which often 

 depends on a correct representation of their minute 

 details. The remainder of the report contains an 

 account of some observations on marine invertebrates, 

 made on animals living in the tanks of the Marine 

 Station at St. James, the description of four new South 

 African fishes, which are well figured, and a continua- 

 tion of Mr. W. Wardlaw Thompson's "Catalogue of 

 Fishes of the Cape Province," with a very full biblio- 

 graphy of each species. 



THE DEVELOPMENT OF BRJTTSH AGRI- 

 CULTURE AND FISHERIES.^ 

 THE advances recommended during the year 

 amounted to 334,903/. Since the commencement 

 of the war advances from the Development Fund have 

 ; been mainly confined to schemes already established 

 with the expectation of continued help from the fund, 



1 Abstracted from theseventh report of the Development Commissioners 

 on their proceedings during the year ended March 31, 1917. 



for which just sufficient advances have been recom- 

 mended to secure continuity. 



As regards new schemes, the Commissioners have 

 contmued to recommend expenditure upon the prepara- 

 tion, by way of preliminary survevs and reports, of 

 projects of development for commencement after the 

 war when the emplovment of labour upon a large scale 

 may be desirable. They have also recommended ex- 

 penditure on certain new schemes in order to meet 

 war conditions, particularly in connecton with food 

 supply and natural products. The two most important 

 new advances recommended by them during the year» 

 namely, 125,000/. for purchase of an estate for sugar- 

 beet growing, and 50,000/. for improving the fish food 

 supply by installing motors in fishing-boats in England 

 and Wales, fall under this heading. These two ad- 

 vances amount to one-half of the whole sum recom- 

 mended for the 3'ear. A largely increased supply of 

 plants for afforestation purposes, and increased grow- 

 ings of flax for aeroplane cloth, are other instances 

 where war conditions have called for extra expendi- 

 ture from the Development Fund. 



Agriculture and Rural Industries. 

 Agricultural Research and Education, etc. — For the 

 continuance of the research scheme in England and 

 Wales during 1917-18 the following grants from the 

 Development Fund to the Board of Agriculture and 

 Fisheries have been sanctioned : — ■ 

 Grants to colleges and institutions in aid of — /^ 



(a) Scientific research and experiments ... 19,600 



(b) The extension of advisory and local in- 

 vestigation work 8,oco 



(c) Special investigations and research, and 



scholarships ' ... 2,400 



(d) Inquiries and experiments, etc., by or on 



behalf of the Board '. .. 600 



Expenses of administration 880 



Less amount not payable from the Development 

 Fund ... 



31,480 



1,750 



29,730 



NO. 2515, VOL. 100] 



Research in animal pathology to be undertaken 

 at the Board's veterinary laboratory, 

 1917-18 .'.. 2,000 



Research Institute in Plant Patholog\- at Kew 1,358 



The proposed expenditure in respect of the grants 

 for research institutes and advisory centres contem- 

 plates only the carrying on of existing work, and no 

 new work of any im.portance was started last year 

 with the exception of investigations bearing directly 

 on the war, with which some of the workers are 

 engaged, particularly at Cambridge University. 



A grant to the Board of Agriculture and Fisheries 

 of 16,445/. w^s made in aid of agricultural and dairy 

 education during the year 19x7-18. 



A grant of 3700/. was sanctioned to enable the Board 

 in consultation with the Commissioners to assist new 

 emergency schemes of an educational or quasi-educa- 

 tional character. A grant of 1330/. was made to the 

 Imf>erial College of Science and Technology for an 

 investigation during 19 17 into the effect of electrical 

 discharpfe on the growth of crops. 



The Commissioners have recommended an advance of 

 4.00/. to the North of Scotland College of Agriculture 

 for the continuation during 1916-17 of research work 

 which is being carried out under the supervision of a 

 joint committee of the University of Aberdeen and of 

 the college; an advance of 315/. to the University of 

 Edinburgh for the continuation during the period 



