PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 491 



allowed to pass from the stills, some being taken oif at a higher temperature 

 than others, and to these various names are given; indeed it is a matter of 

 choice witli those who send it to market, whether they make it benzole, 

 benzine, or any other name by which the lighter oils are known. There 

 is nothing known in commerce as carbon spirits. 



Mr. Rowell read an extract from a paper relating to the oil wells of 

 Canada, which were about being revived, from which it appeared that the 

 average yield of the Canada wells was about 1,000 barrels a day. 



The Chairman said that in all the oils there was an excess of carbon, and 

 they therefore would not burn without smoking. The formulas for some 

 illuminating compounds are as follows: Olifiant gas 4 C4 H; oil gas 8 

 Cg H; spermaceti 32 Cj-i H. These substances burn without smoke. It 

 will be perceived that there is an equal number of atoms of carbon and 

 hydrogen in each; but in substances which give a brilliant flame, yet are 

 liable to smoke, there is always an excess of carbon atoms. Thus cam- 

 phene or purified tiu'pentine contains 20 C to 16 H., and in all the rock oils 

 tliere is an excess of carbon. The proportions of carbon and hydrogen 

 have not been determined by the chemists. 



A New Alarm. 



Prof.Tanderweyde presented a model of a new burglar alarm; it consists 

 of two gas burners, one above the other, about eight inches apart; between 

 these burners there is a tube about an inch and a half diameter, and seven 

 inches long, the upper burner to be kept lighted during the night; an at- 

 tachment is made from the lower burner to the door or window, which, on 

 being opened, causes the gas to escape from the lower burner, and ascend- 

 ing through the pipe to lighted jets above, gives rise to a series of explo- 

 sions, say some 50 in a second, by which a noise similar to a steam whistle 

 is produced, the tone of which can be varied according to the size of the 

 pipe or tube between each jet. He tried the experiment with a stovepipe, 

 and the noise was equal to the roar of a lion. It could also be used as a 

 fog signal and various other purposes. It is constructed on the principle 

 of the chemical harmonica. 



The Chairman said the instrument called the chemical harmonica waa 

 long known, but never before applied to any practical purpose; he was 

 glad to see that Prof. Vanderweyde had made a valuable application of sci- 

 ence to the arts. 



Prof Vanderweyde, in reply to an inquiry, said he had made several 

 experiments to destroy the odor in the oils, but thus far had not fully suc- 

 ceeded. 



The subject of " Petroleum " waa continued for the next evening. 



Adjourned John W. Chambers, Secretary. 



