354 LEEDS chemists’ association. 
The following gentlemen were elected members:—Messrs. S. G. Wheeler and H. 
Moses. 
To the museum was presented, through Mr. Evans, a specimen of bark, resembling 
Calisaya bark, recently introduced from Para, by J. E. Howard Esq. 
The following letter from Professor Hamilton, detailing the experiments referred to in 
his letter read at the last meeting, was read. 
Dear Sir,—I send you the details of the experiments on dialysis, made in July and 
August, and since repeated with the same results. 
Experiment 1.—A portion of egg-albumen was mixed with about ten times its volume 
of water and filtered; a drop of the clear filtrate, when evaporated on a slip of glass, left 
a deposit which turned black on further heating over the gas flame. 
Experiment 2.—Placed the filtrate in a dialyser, and the dialyser in an evaporating- 
basin on the surface of a clear, filtered, weak solution of common salt. After seven days 
the liquid in the basin was transferred to a glass beaker and examined,—no albumen could 
be detected. 
Experiment 3.—Washed the dialyser, and introduced a fresh portion of solution of 
albumen. The lid of a platinum crucible was placed in the dialyser, and the positive 
electrode of a cell of Daniell’s battery was placed in contact with the lid ; the negative 
electrode was placed in the solution of salt on which the dialyser rested. After eight 
days the solution of salt was examined for albumen. An abundance of flocculi appeared. 
Some of these, taken out on the end of a glass rod and heated on a slip of glass, darkened 
in colour, and finally became black and charred. 
Experiment 4.—Arranged the experiment as before, but without the battery, and sub¬ 
stituting solution of gelatine for the solution of albumen. After fourteen days, examined 
the solution and found that gelatine had passed through. 
Experiment 5.—Washed the. dialyser thoroughly, and allowed it to become dry. Pure 
water was poured into it, it was placed in a clean, dry, evaporating basin, and allowed to 
stand for seven days. At the end of that time not one drop of water had passed 
through. 
Experiment 6.—Being satisfied from experiment 5, that the dialyser was not porous, I 
introduced a fresh solution of gelatine, and placed the dialyser on the surface of pure 
water, and allowed it to remain for a month. At the end of that time the water was 
placed in an evaporating-basin and boiled,—it gradually darkened in colour, thickened, 
bubbled up, emitting a smell like that of glue, and left an abundant residue of charred 
gelatine. I am, yours very respectfully, 
George Hamilton. 
H. Sugden JEvans, HJsq., Hon. Sec. Chemists' Association. 
M. Murphy, Esq., read the paper of the evening, “ On the Products of Coal Tar.” 
A short discussion ensued. A vote of thanks was cordially accorded to Mr. Howard, for 
his donation, Professor Hamilton for his letter, and Mr. Murphy for his excellent lec¬ 
ture, and the meeting separated. 
The Sixth General Meeting was held on Thursday, 17th December, at the Royal In¬ 
stitution ; the President in the chair. 
Mr. Henry Bird exhibited and explained his new Automaton Petroleum, or Mineral 
Oil Testing Apparatus. Not having received the drawing illustrating the apparatus, 
the description of the same is unavoidably deferred. 
LEEDS CPIEMISTS’ ASSOCIATION. 
The Fourth Ordinary Meeting of the Association for the session was held on the 
evening of January 13, 1864, at the School of Art; Mr. Thompson in the chair. 
Mr. Yewdall called the attention of the meeting to a bottle for keeping essential oils. 
It did not claim novelty of form, since it was a modification of the bottle much used 
for castor oil, glycerine, etc., but Mr. Yewdall thought that its merits for keeping 
essential oils had not been recognized so much as they deserved. It prevented evapora- 
