Proceedings of the British Association. 357 



are not yet complete ; but he was inclined to think the difference 

 between the two cases to be apparent, only, and not real. He is 

 continuing his investigations, and hopes to report further on a 

 future occasion. 



Dr. Schnnk read a paper on Hematoxylin, the Colo?~ing Prin- 

 ciple of Logwood, by Prof. O. L. Erdman, of Leipsic. The he- 

 matoxylin used by the author in his experiments, was prepared 

 by the process of charcoal. In a state of purity, hematoxylin 

 is not red ; it is in itself no coloring matter, being merely a sub- 

 stance capable of producing coloring matters in a manner similar 

 to lecanorin, orcein or phloridzin. The colors which it produces 

 are formed by the simultaneous action of bases, (particularly 

 strong alkalies,) and of the oxygen of the atmosphere. By the 

 action of these it undergoes a process of eremacausis, which after 

 forming coloring matters, ends in the production of a brown sub- 

 stance resembling mould. The color of hsematoxylin varies from 

 a pale reddish-yellow to a pale honey color. The crystals are 

 tfansparent, have a strong lustre, and may be obtained a few lines 

 in length. Their form is a rectangular four-sided prism, some- 

 times with a pyramidal summit. The taste of hEematoxylin is 

 similar to that of liquorice. With excess of ammonia, it forms 

 what the author calls hsematein, analogous to orcein, &c. 



On an economical Voltaic Combination of extraordinary power, 

 by F. W. De Moleyns, Esq. — The author stated that while the 

 discoveries in electro-magnetism gave promise of its ultimate ap- 

 plication as a motive power far surpassing steam, it was matter 

 of much importance to discover a mode of charging or giving 

 attractive power to soft iron, at a cost which should render it as 

 a mechanical agent generally available. The voltaic arrange- 

 ment now produced to the Section, the author believed would be 

 found to possess in a very great degree those advantages so much 

 desired for the proper development of electro-magnetic energy. 

 The combination consisted of an acidulated solution of nitrate 

 of ammonia, in contact with platina, — solution of muriate of 

 ammonia and zinc ; the nitrate solution being separated from the 

 muriate by a diaphragm of wood, biscuit ware, or other porous 

 substance not acted upon by the liquids. The acidulated solu- 

 tion was thus prepared : six ounces of nitrate of ammonia are 

 dissolved in two fluid ounces of soft water, and this solution is 

 then combined with an equal quantity, by measure, of the pure 



