152 



NA TURE 



[December io, 1908 



at different stages of their lives. Further experiirents 

 with much larger batches of fishes will be required 

 in order to provide material for the construction of a 

 complete and convincing^ picture of these movements. 

 In future experiments it would be desirable to deter- 

 mine the sex and maturity as well as the size of 

 the fishes liberated, in order to discover whether there 

 is any difference in the mig'rations of the two sexes, 

 and to distinguish spawning migrations from feeding 

 migrations. 



From time to time, over a period of fifteen years, 

 but, unfortunately, not with anv regularity, experi- 

 mental hauls have been made by the Lancashire au- 

 thorities with shrimp-net, shank-net, and fish-trawl 

 both on the Blackpool closed ground and in the Mersey 

 estuary. The numbers of flat fishes and shrimps 

 caught in these hauls form the basis of two short 

 but valuable papers by Mr. Buchanan-Wollaston. The 

 method adopted in this research is that of reducing 

 the catches to the averajje number caught per hour 

 in different months, quarters, and vears, and then 

 expressing the results in the form of frequency curves. 

 The curves for the monthly data were too irregular 

 to show any general tendency, but by taking the 

 averages for certain combinations of months and for 

 different years, and " smoothing " the curves thus 

 produced, certain interesting features are brought to 

 light. Thus it is clearly seen that on the Blackpool 

 closed ground there has been a steady falling off in 

 the catch per hour of plaice since 1892. No explana- 

 tion is offered of this remarkable phenomenon, which, 

 one supposes, must be due to the increased intensity 

 of fishing on the offshore grounds. It is also shown 

 that the " shank-net " is " superior to the shrimp- 

 trawl in avoiding the capture of young fish, and this 

 with no loss or even a small gain in the capture of 

 shrimps." 



In the Mersey estuary, plaice and soles reach 

 their maximum abundance in late summer and 

 autumn, but it is doubtful whether the data are 

 sufficiently complete to justify the conclusion that 

 soles attain their maximum in August and plaice 

 in September. Finally, an examination of the 

 (smoothed) curves showing the average catch per 

 hour of plaice and soles on the Mersev banks shows 

 some remarkable fluctuations, those of the two species 

 being complementary, so that in those 3-ears when 

 plaice were least abundant, soles attained their maxi- 

 mum. The importance of such researches as these 

 from the point of view of the local fisheries scarcely 

 requires to be emphasised. 



In addition to these papers. Dr. H. Bassett con- 

 tributes one on hydrographic observations, and Mr. 

 Johnstone one on fish parasites. 



As regards the work of the Piel hatcherv, while 

 it is questionable whether any demonstrably useful 

 purpose is being served by annually " dumping " in 

 the Irish .Sea millions of newly-hatched fry of plaice 

 and flounder, it seems not improbable that the holding 

 of classes for fishermen is as effective in practice 

 as it is excellent in theorv. 



It will thus be seen that the work which these 

 two institutions are vigorously carrying on in the 

 interests of marine biology in general, and the local 

 NO. 2041, VOL. 79] 



fisheries in particular, is of a comprehensive and 

 many-sided character. The expenses of this work 

 appear to be met by funds derived from several dis- 

 tinct sources. For example, the cost of holding classes 

 for fishermen at Piel is defrayed bv a grant from the 

 education committee of the Lancashire Countv 

 Council, while Mr. Pearson's work on the crab was 

 done and published, we are told, under the auspices 

 of the Lancashire Sea Fisheries Committee, with 

 the aid of grants from the Board of .Agriculture and 

 Fisheries, the University of Liverpool, and the Liver- 

 pool Marine Biology Committee. This appears to be 

 a somewhat complicated arrangement, which per- 

 haps, however, has the advantage of the safety which 

 is popularly supposed to reside in numbers. It shows, 

 at any rate, that marine biology in Lancashire does 

 not lack friends. \V. W. 



LABORATORY ARTS. 

 Laboratory Arts. A Teacher's Handbook dealing 

 with Materials and Tools used in the Construction, 

 Adjustment, and Repair of Scientific Instruments. 

 By Dr. George H. Woollatt. Pp. xii+102 ; with ik) 

 diagrams. (London : Longmans, Green and Co., 

 1908.) Price 3s. 6d. net. 

 CKILL and wide knowledge in "laboratory arts" 

 are much rarer attainments than the accumula- 

 tion of ideas relating to abstract or even to mathe- 

 matical physics, yet, without making comparisons, it 

 is essential to the success of the experimentalist. I f 

 it were not for the fact that such skill and know- 

 ledge are not to be acquired by mere reading of a feu- 

 books, it might be thought that the disproportion 

 alluded to above might be the result of the still more 

 marked disproportion between books of the text-book 

 type dealing with the two branches of attainment. 

 .Actually, it is probably the cause, or partly so, and 

 it may be also that the scarcity of books such as 

 that now being noticed is due to a belief on the part 

 of the few qualified to write them that, dealing as 

 they do with a subject which directly is not an 

 examination subject, there will be no great demand 

 for them. Whatever the cause may be of the scarcity 

 of books dealing with laboratory arts, they are actually 

 invaluable, and from Faraday's chemical manipula- 

 tion onwards they furnish the experimentalist with 

 ideas as to how to accomplish his purpose. 



Dealing as such books must do with all the proper- 

 ties of all materials and with the means peculiar to 

 each whereby they may best be cut, distorted, attached, 

 or protected, it is not possible for any one writer to 

 be equally strong in all parts. A writer is certain 

 to be specially strong in certain departments ; let it 

 be so ; those who are or might be his fellow-writers 

 of similar books will be quick to recognise these 

 parts, and to benefit by them. Conversely, of course, 

 no one book is likely to be quite satisfactory in deal- 

 ing with every kind of operation where they are so 

 diverse. Leaving now generalities and coming to 

 the " Laboratory .Arts " as presented by Mr. Woollatt, 

 we find an admirable choice of material admirably 

 presented. It must bs understood that the teacher 

 or the experimentalist probably is not and may not 



