68 REPORT — 1870. 



a salt of ammonium, is employed to deposit brass. This solution, however, evolves 

 hydrogen copiously, and is only -workable by means of two (irove's cells. The au- 

 thor finds that the evolution of gas may be either totally stopped or much lessened 

 by dissolving as much of the metallic cyanides as the solution will take up, and 

 then further charging the solution with the copper and zinc oxides. The evolution 

 of gas may be totally stopped by the further addition of cupric ammonide, which 

 may possibly carry the combined oxygen to the cathode, according to the following 

 equation : — 



At the cathode before chemical reaction. At the cathode after chemical reaction. 

 {Cu,0,4NH3 + 4H,0} + H^ = Cu^ + 4NH3 + 511,0, 



Cupiic ammonide. Hydrogen. Copper. Ammonia. Water. 



Malaguti and Sarzeau's formula for cupric ammonide being iised, — that is to say, 

 before decomposition or chemical reaction takes place, the whole of the cupric am- 

 monide, together with the eliminated hydrogen, goes to the cathode ; after the de- 

 composition or chemical reaction has taken place, metallic copper is deposited, am- 

 monia is in solution, and water is formed. 



In treating the ordinary cyanide copper solution for the prevention of the evolu- 

 tion of hydrogen, the zinc cyanides or oxides, mentioned in the instance of the brass 

 solution, are left out. 



When the evolution of hydrogen has been stopped, a single Smee's cell is suf- 

 ficient to deposit the alloy ; but, in practice, a smgle Grove's cell, or equivalent 

 magneto-electric power, is employed, in order to shorten the time of immersion in 

 the electro-coating bath. 



The author prefers to use potassic cyanides and neutral ammonium tartrate, 

 when mixed with water, to form the solvent solution for either brass or copper. 

 The quality of brass (yellow or red) depends upon the heat of the solution. 



Acid solutions, in general, give a spreading or matted deposit, alkaline solutions 

 a bristling- one. The contact of the coating is promoted by working the solution 

 hot. The article should be pickled, scrubbed with sand, washed, scrubbed with a 

 portion of the depositing solution, and then placed in the depositing trough. After 

 deposition, the article is washed and dried in hot mahogany sawdust. Com- 

 plete protection from rust, and a satisfactory coating for any purpose, is given 

 by the use of the acid-depositing bath subsequent to that of the alkaline bath. 



Specimens of electro-deposited brass, by the author's processes, were exhibited. 



On the Weldon Process for the Manufacture of Chlorine. 

 By Walter Weldon, F.C.S. 



Communication respectinff a Besolution of the Committee of Section B on the 

 2wo]iosecl establishment of a New School of Applied Science hy Government. 

 By Professor A. W. Williamson, F.B.S. 



Professor Williamson communicated to the Section a Resolution which had 

 been passed in identical terms by the Committees of three Sections, viz. those of 

 Physics, Mechanics, and Chemistry. It was to the following effect : — 



" That in the opinion of this Committee it is inexpedient that new institutions 

 for the teaching of science, pm-e or applied, such as the proposed Engineering Col- 

 lege for India, should be established by Government, until the Royal Commission, 

 now holding an inquiry into the relation of the State to scientific instruction, shall 

 have issued their report. 



" That the Council of the British Association be requested to consider this opi- 

 nion, and, should they see fit, to urge it upon the attention of Her Majesty's 

 Government." 



It is well known that there are in the Universities and Colleges of the United 

 Kingdom complete and systematic courses of instruction in the various branches of 

 science required for engineering pursuits, and that young men do obtain through 

 them the needful scientific preparation for professional work in engineering. There 



