211 



Whittell, who was in England for nearly two years, took a great interest in 

 the Club and formed a number of friendships among the members. He had 

 not forgotten them, and had not only sent them some communications, but 

 had forwarded him a newspaper in which was mentioned how he had 

 brought the subject of diffraction spectra before the Microscopical Society of 

 Victoria to their great astonishment. It was quite a new idea to them. 

 Dr. Whittell took great interest in the optical parts of the microscope. 



Mr. W. Dalton Smith said those who had experienced difficulty in sealing 

 glycerine mounts would find the plau he adopted useful. He made a pre- 

 paration of five parts of asphalt, one of the newest Canada balsam, and one 

 of gold size, by measure, with sufficient benzole or turpentine to make the 

 mixture sufficiently thin for use. He then made a cell of the size required 

 and left it until wanted. It would remain sticky for one or two months, so 

 much so that the cover would adhere quite firmly with simple pressure, and 

 all trace of glycerine could be washed off. The slide could then be rubbed 

 dry without fear of injuring the object or moving the cover, and could be 

 finished with Ward's brown cement or any preparation of that kind. He 

 believed such slides would be found permanent. 



Mr. T. C. White remarked that he had used coaguline, but found that it 

 contracted so much that the cover glass was broken all to pieces. 



Mr. Hailes said he used ordinary gum mucilage, which was entirely 

 changed in character by using the bichromate of potash. The gum should 

 not be allowed to dry, but merely to set, then by dropping a little bichromate 

 on the cover, it acted rapidly upon the gum, which by exposure to the light 

 became insoluble in water. The slide could then be washed off and 

 finished. 



Mr White observed that he did not know the effect of adding bichromate 

 of potash to gum. He knew it acted in that way with gelatine. This was 

 useful for making large trays water-tight, giving them a coat of glue and 

 then treating with bichromate of potash. 



The President suggested that perhaps gum tragacanth could be used. It 

 would certainly be insoluble. 



Mr. Hailes replied that he thought gum tragacanth would shrink too 

 much to be used for that purpose. 



Mr. T. C. White reminded the members of the suggestion he had made in 

 a casual communication to the Club some time ago. A mixture of gold 

 size and indiarubber dissolved in benzole, to which was added some of the 

 shellac called French glue. It required to be put on thin and dried very 

 quickly. When dry another ring could be run on, and the slide finished in 

 the usual way. This cell gave sufficient elasticity to allow the glycerine to 

 expand, and any kind of finish could be used. 



The cordial thanks of the meeting were then given to Dr. Whittell for his 

 communication. 



The President, in announcing the arrangements for the ensuing month, 

 specially referred to the satisfactory demonstration given at the last con- 

 versational meeting, and mentioned that the second of the series would be 

 given on the 12th proximo " On Photomicrography," by Mr. T. C. White. 



