TRANSACTIONS OF SECTION D. 913 



available argument has been examined, and no scientific basis remains on which 

 to uphold such a proposal. 



The conclusions, therefore, briefly are:— 



1. That the haste for additional closures (to the original areas of the Forth, 

 St. Andrew's Bay, and Aberdeen Bay), after a year or two's work, and before any 

 definite scientific result could be obtained, was unnecessary. 



2. That no increase of the food-fishes has followed the closure, the high and 

 low numbers succeeding each other in such a way as can only be explained by the 

 irregularities and uncertainties invariably attendant on fishing operations. 



3. That, because the first five years of the decade had a higher average than 

 tbe second, it therefore followed that diminution of the fishes had occurred, and 

 called for further closures beyond the three-mile limit to remedy it, is shown to 

 rest on insecure data. 



4. That the closure of the Moray Firth cannot be supported on scientific 

 ijrouuds. 



5. That the closure of the three-mile limit, or even the thirteen-mile limit, can 

 have little eflect on a plan so gigantic as the distribution of invertebrates and fishes 

 in the ocean. 



6. That the interference of man — specially by closure on the one hand — is 

 powerless to increase the food-fishes of the sea, or, on the other hand, by eager 

 fishing, to reduce them to vanishing point. 



7. On a Circulatory Apparatus for Use in Researches on Colour Physiology 

 and other Investigations. By F. W. Keeble, M.A., and F. W. 

 Gamble, M.Sc, Demonstrators in Owens College, Manchester. 



In a research on the colour physiology of certain marine crustaceans ( Virbius 

 oarians, Sic.) we have found it necessary to devise an apparatus which shall allow 

 of the passage of a constant current of sea water through a number of observation 

 dishes so arranged in series that any one maybe disconnected without interrupting 

 the flow through the others. 



The constancy of flow is effected by fitting the aspirator bottle, the water 

 reservoir, with a pressure tube and an exit tube beginning with a very fine point. 

 The water is siphoned through the observation chambers and escapes at a point indi- 

 cated in the diagram which was exhibited to the Section. At the outset we find 

 our attention directed to the question as to whether change in the aeration of the 

 water or change of the water itself is the more efficacious in maintaining the animals 

 in a healthy condition. For this purpose we connect with our main apparatus 

 another set of observation dishes, also arranged in series, and through which air 

 is drawn by the aspirator, the content of which is such as to allow the current to 

 run uninterruptedly at a fair rate for twelve hours or more. 



By using a series of observation dishes in each case we are able to compare the 

 effects of dittuse light, darkness, and monochromatic light on the colour, and on the 

 chromatophores of the animals submitted to the experiment. 



Monochromatic light is obtained by the use of colour-filters wliieh we have 

 constructed somewhat on the model of Landolt's ' Strahlenfilter,' and which fit 

 closely on our observation dishes, the sides of which are darkened. 



The 'colour-filters' are made of two- or three-chambered vessels containing 

 appropriate fluids in exactly requisite thicknesses. 



For the further examination of the immediate effects of light, darkness, and 

 monochromatic light we employ a horizontal microscope fitted with a ' live box ' 

 which can be connected to the water circulation and below the stage with a 

 colour-filter. 



On the conclusion of the light experiments referred to, we intend to examine 

 the efiects of gases and of anaesthetics, &c., on the nervous system and the chroma- 

 tophores. 



This apparatus, though devised for the research on colour physiology is one 

 1898. 3^ 



