182 



May 23rd, 1873.-— Dr. R. Braithwaite, F.L.S., President, in the 



Chair. 



The following donations to the Club were announced : — 



" The Monthly Microscopical Journal" ... from the Publisher. 



" Science Gossip " ,, 



*' Proceedings of the Geologists' Association ... the Association. 



" President's Address, &c., of the West Kent ) ,, Society 



Natural History Society " ^ 



"Withering's Botany," 2 vols Mr. Jas. Watkins. 



The thanks of the Club were unanimously voted to the Donors. 

 The following gentlemen were ballotted for, and duly elected members of the 

 Club :— Mr. Alfred Coles, Mr. Robert R. F. Davey, Mr. William Gregory, Mr. 

 George C. Karop, Captain Loftus F. Jones, R.N., Mr. W. H. Kennell, 

 Lieut.-Colouel J. C. Salkeld, Mr. James H. C. Stewart, and Dr. John Whit- 

 more. 



There being no formal paper to be read before the meeting, 

 Mr. T. C. White thought it might be interesting to members to know the 

 particulars of the last mode of producing crystals of hippuric acid by means of 

 sulphur fumes. He was induced to bring the subject before them because of a 

 letter which he had lately received from Mr. Furlonge, in which that gentleman 

 seemed very much struck with the method of crystallization by breathing upon 

 a film, and in which he had also asked how the effects were produced by the 

 sulphur fumes. The ordinary method was to make a saturated solution of the 

 salt in absolute alcohol, which should be heated in order to cause it to take up 

 as much as possible. Then a small quantity of the warm solution was taken up 

 in a warm dipping tube, ami placed upon a warm slide, over which it would flow 

 evenly, and would, as it cooled, form a thin transparent film. In a short time — 

 according to the amount of moisture in the atmosphere — crystallization would 

 begin to start from a number of centres, and would, if not interfered with, form a 

 number of circular crystals. But if, when the circular crystals were beginning to 

 form they were breathed upon, a number of fringed crystals would at once begin 

 to start from all round their edges. If, instead of breathing on them, they were put 

 under a bell-glass with a little vapour of ammonia, fern-leaved crystals would 

 be formed, and by varying the vapours the results would be varied accordingly. 

 Seeing how much the foi-m of crystal was aff'ected by the amount of moisture 

 brought into contact with it, he thought that if he could cover the film with 

 something whicb would rapidly absorb moisture, some curious eff'ects might 

 result. Knowing, therefore, the power which sulphuric acid possessed of ab- 

 sorbing moisture, he placed the films in contact with sulphurous acid from the 

 fumes of burning sulphur. Having covered the film with it he laid it by to cool, 

 and found that the whole crystallized in a beautiful fern-like arrangement, but 

 with this peculiarity — that the fronds were all of that peculiar wavy variety 

 which had been so much admired in the specimen slides he had brought to the 

 Club to exhibit, and which, when produced in the same way, were found to be 

 generally constant, thougli there was no end to the variety produced by breath- 

 ing upon them. Another curious form might be obtained by placing a glass 

 cover over a film, and then running a little benzole round it; the crystals in this 

 case took the form of those of uric acid, and appeared as modifications of the 

 ordinary dumb bell crystals. 



