THE director's REPORT. 223 



tlie fislierman in the employ of the Association^ W. Roach, gave up 

 his place to return to his old work, and an experienced trawl fisher- 

 man, E. G, Heath, was engaged in his place. The loss of Roach's 

 services is to be regretted, as he possessed a minute and peculiar 

 knowledge of the rocks and shoals in the neighbourhood of Plymouth, 

 and could dredge in many places where other fishermen would not 

 venture to try. 



The Association has incurred a considerable expense in altering 

 the connection between the storage reservoirs and the feed pumps. 

 This operation involved the cutting through in two places of a solid 

 concrete wall four feet thick, and the purchase and erection of 

 new supply pipes, valve boxes, and fittings. The result has been 

 most satisfactory. The pumps run more smoothly, the circulation 

 of the water is improved, and the sediment which accumulates at 

 the bottom of the storage reservoirs is undisturbed. 



It has been asserted recently that the Plymouth Laboratory is 

 placed in an unsuitable position as regards water supply, and that 

 the sea-water in circulation is drawn from a contaminated source, is 

 turbid, and below the normal density of sea-water. I may take this 

 opportunity of giving an emphatic denial to these statements. 



It is true that on the ebb tide, and in neaps at all tides, the 

 water of the Sound below the Laboratory is polluted by the material 

 carried out of the Cattewater, and is often of insufficient density. 

 But in spi-ing flood tides a large volume of water flows direct to the 

 shores beneath the Laboratory from the sea, and it is only on these 

 occasions that water is pumped into the storage reservoirs. Usually 

 the water when first pumped in has a density of 1*0255 or 1'0266, 

 and after it has been a short time in circulation its density is raised 

 by evaporation to 1'027, after which we have to add fresh spring- 

 water to make up for evaporation. By keeping both storage reser- 

 voirs full we have always a reserve of 100,000 gallons of sea- water, 

 from which the circulation is supplied. Since the alterations in the 

 supply pipes we are able to circulate from both reservoirs at once, 

 and as it takes sixteen hours to pass their united contents through 

 the circulation, the water in them is very little disturbed, and there 

 is ample time for the settlement of all solid matter which it may 

 contain. The water now in circulation is, and has been for several 

 mouths past, remarkably pure and bright, and its density is per- 

 fectly normal. I cannot say more than that it is satisfactory in 

 every respect. 



No doubt visitors may have observed that the water in the 

 aquarium has occasionally been of indifferent quality during the first 

 twelve months' working. This was partly due to the imperfections 

 in the original supply pipes, partly to the fact that the tanks were 



