183 



The President expressed his thanks to Mr. White for coming to the rescue on 

 that barren evening mth so interesting a communication, and invited discussion 

 or remarks upon the subject. 



Mr. Golding said he had no experience in the matter, and therefore wished to 

 ask whether the crystals of Hippuric acid were of a permanent character, or 

 whether they required to be mounted ? 



Mr. White, in reply, stated that he found the crystals were easily preserved 

 by a very little fluid balsam run under the cover of the slile ; this was all that 

 was required. He had mounted them sometimes in castor oil, but found some 

 difficulty in keeping the oil in. He had also tried benzole, but that was found 

 to alter the character of the crystals altogether. 



The President observed that castor oil had been long used, with success, as a 

 preservation of crystals, but the difficulty mentioned by Mr. White of keeping 

 it in the cell often caused inconvenience. 



Mr. Alpheus Smith inquired how the square form of the crystals was pro- 

 duced ? 



Mr, White said this certainly was a very pretty form, and was much admired as a 

 toy slide. It was produced by obtaining a film on the glass slide, and then 

 combing it crossways with a fine comb, when the crystals started at once from 

 all the scratches, and met in the middle of the squares. Pricking the film in 

 different places would vary the form of the crystals ; they would start from every 

 point touched with the needle, so that a pattern of any kind could be produced. 

 He had even caused them to form his initials by pricking the letters rapidly on 

 the film. 



Dr Matthews said that there was a method of mounting crystals in castor oil. 

 which he had tried with success, and he thought it might be worth mentioning, 

 After having obtained the crystals upon a glass slide, in the usual way, he 

 placed it upon a turn-table, and taking a piece of soft wood — the end of which 

 had been bruised a little so as to make it brushy — he cleared away all but a 

 circular patch on the middle of the slide. He then made a cement ring or cell 

 round the circular spot, taking care that there was a small margin left between the 

 crystals and the cement. When this cell was properly dry, he took a glass cover 

 and placed it nearly all over the cell, and then by means of a pipette filled the 

 cell carefully with the oil, and slid the cover over it into its proper place. A 

 spring clip of low power was next applied to the cover, and after all the super- 

 fluous oil had been cleared away, a ring of strong cement or goldlsize was run 

 round the cover. 

 In reply to a question from Mr. Marks, 



Dr, Matthews said that this method was of course only applicable to such 

 kinds of crystals as castor oil would preserve. He also said that it was desirable 

 that both the oil and the slide should be slightly warmed in order to increase the 

 fluidity of the former. 



The President reminded members that the annual meeting of the Club was 

 approaching, and that the names of those gentlemen who were to be elected to 

 fill vacancies on the Committee must be proposed at their next ordinary meeting; 

 members should therefore come prepared to nominate those whom they were 

 desirous of seeing elected. He also wished to say that several important matters 

 had lately been engaging the attention of the Committee, which he thought it 

 desirable to lay before the meeting. The first of these was the Journal, and 

 with reference to this, it had been strongly felt by the Committee that in its 

 present form it was not worth the large sum of money which it cost the Club 



