838 PROCEEDINGS OF THE SOCIETY. 



be somewhat short, but it must be remembered that the apparatus 

 wasmerely a model. If, however, any difficulty were experienced, there 

 was in it the slightest reason why the illuminant should not be carried 

 over the back, or that longer supporting castings should be used. 



Dr. Spitta objected that he thought it might strain the apparatus. 



Mr. Barnard said that it could be supported so that its weight came 

 over the centre of gravity of the swinging tail-piece. Mr. Scales thought 

 that the apparatus would not be so easy to use from the point of view of 

 centering in comparison with the triangular bar. So far as his (Mr. 

 Barnard's) experience went, the triangular bar was not entirely satis- 

 factory. One had to rely so entirely on the setting-up of the fittings on 

 the triangular bar, and also on the extent to which the olamping-screw 

 was tightened. He ventured to suggest that triangular bars were even 

 open to improvement. By altering the shape of the groove in the bar 

 it would be possible to change the direction of the strain from a lateral 

 to nearly a vertical pull. 



Dr. Spitta said there was no need to screw up. 



Mr. Barnard replied, that even if reliance were placed on the fitting, 

 there was still the question of the lateral adjustment of the lens to the 

 optical axis. He thought the main point, however, was that of cost which 

 had been raised by Mr. Scales, and which he ought to have dwelt on. He 

 thought really it should be the cheapest apparatus yet built considering its 

 efficiency, because there was no fitting to be done. A pattern was made in 

 each case, from which two castings were taken. So far as the geometric 

 solids went they were rough castings. All bolting together was done by 

 means of holes provided in the castings, and the whole could be braced 

 up together. It would be difficult to imagine an apparatus in which 

 there was less work, and in all such appliances it was the labour, and not 

 the material, that cost money. 



The President said he was very glad indeed to hear this account of 

 the cost. He thought that anyone who, like himself, had taken so many 

 photomicrographs for many years with an inferior instrument, would be 

 full of envy of such a machine. There was one point about the appa- 

 ratus on which he had to congratulate Mr. Barnard, and that was its 

 compactness as compared with Sir. Barnard's earlier models, one of which 

 he remembered somewhat resembled a suspension bridge in shape 

 and size. He thought from what he could see of the model that this 

 instrument would be extremely rigid. The thanks of the Society would, 

 he was sure, be cordially accorded to Mr. Barnard for the very interesting 

 aud important illustration of an apparatus which would prove to be of 

 the greatest value, especially if the cost was what Mr. Barnard had led 

 them to hope. 



The vote of thanks proposed by the President to Mr. Barnard was 

 carried with acclamation. 



A paper by the Rev. Hilderic Friend on " British Enchytraeids II. ; 

 the Genus Fridericia," was read by Mr. Shillington Scales in the absence 

 of the author. Mr. Scales said that as the paper proved to be of a very 

 technical character, he would merely deal with those points of salient 

 interest. In conclusion he said that there followed a I0112; classification 



