220 The hish Naturalist, 



developed in, or near, the crystals of hornblende ; the lattermaking up 

 about 20 per cent, of the total bulk of the rock. In the mass, the rock 

 has a slight schistose structure, and is said to yield from 80-100 oz. of 

 gold per ton. The mean result of several experiments gave its sp. gr. as 

 2 85. A few cr3^stals of sphene, and some of titanic iron, appear in the 

 section. 



RE;y. Canon Russell showed a preparation of the feathers of a duck 

 showing the scales, to the peculiar structure of which their irridescence 

 is evidently due. The feathers had been boiled first in caustic potash, 

 and reduced almost to a pulp, and then put up in glycerine jelly. Their 

 metallic lustre could be plainly seen after this treatment under reflected 

 light. The barbs seem to be composed of a single file of cells, marked 

 longitudinally with fine lines like those on the scales of the wings of 

 the Lepidoptera, which bring out the colours found on all such striated 

 surfaces. 



These stride appear to have been noticed before ; but in the centre of 

 each scale there is a well-marked oval or round figure, of which the 

 exhibitor could get no account from any book. It was conjectured that 

 they might be the nuclei of epithelial cells. If this be so, the only 

 way of accounting for their absence in the scales of butterflies and 

 beetles, is that on these latter the scales are simply inserted in sockets, 

 and are not organically connected with the membrane on which they are 

 set. The cells of the barbs seem to grow out of the substance of the 

 feather, and cannot be detached from it. The feathers examined were 

 those of the Peacock, the Teal, and an Argentine Duck ; in all the same 

 structure is to be found. 



Belfast Naturalists' Field Club. 



June 15. — A party of twenty-five proceeded by the Northern Counties 

 Railway to Limavady and the valley of the Roe, On arrival at the 

 prosperous clean town of Limavad}-, a start was made for the Glen, a 

 distance of a couple of miles. The first halt was made at O'Cahan's Rock, 

 where the party spent a pleasant hour botanizing, lunching, and 

 photographing, the splendid crag forming a feature hard to surpass. 



Mrs. Leebody, the well-known Derry botanist, joined here, and her 

 local knowledge proved useful throughout the day. A steep climb from 

 the river-bed brought all to the top of the precipitous rock, from which 

 the view of the Roe Valley was very beautiful. The Dog's Leap was then 

 made for, where the curious pot-holes below the bridge came in for a 

 share of observation, and where those members interested in engineer- 

 ing (among whom Mr. A\'. A. Traill, of Bushmills, was prominent) 

 enjoyed an inspection of the electric light station and sawmill owned 

 and worked by Mr. J. E. Ritter, J. P., to whom the Club were indebted 

 for this pleasure. The dynamos are driven by a turbine, the mill by an 

 ordinary wheel, and a new pit is in process of formation for an additional 

 turbine. After enjoying the cool water of the well, the return journey was 

 begun, passing down the other side of the river through woods where 

 the most delightful views of water and mountains were obtained. 

 Here the botanists were pleased to find a great profusion of Lastnca 

 (€inula, a fern which is locally uncommon. Mr. Ritter's house at Roe 

 Park was soon reached, and by his courtesy was thrown open to those 

 of the party who cared to inspect a most perfectly ai)pointed amateur's 

 workshop. 



