340 KANSAS CITY REVIEW OF SCIENCE. 



new and untried experiment, the employing of negro labor in iron manufacturing 

 establishments in this country. Before the war negroes found steady and profit- 

 able employment in rolling mills in the South, and the writer had occasion fre- 

 quently during the war to observe the fact that negroes were almost exclusively 

 employed in such establishments in Richmond and Atlanta, and also in some 

 works on the Etowah River, in Georgia. We have knowledge of some ex- 

 tensive coal mining operations now being carried on in Ohio, the entire force 

 of laborers being negroes, many of whom have acquired homes and worldly goods 

 there as the result of their work — many of them having money to their credit in 

 bank. Some technical education would be necessary of course to fit these people 

 for such duties; but if such a class of labor as is now used, or has been used up 

 to the late strike, becomes unavailable, it would be worth while for manufacturers 

 to turn their faces to the South and at least make the effort to utilize the negro as 

 a worker in iron. The experiment should be tried. — Age of Steel. 



CHEMISTRY. 



WATER GAS- 

 BY A. P. H. 



When steam is brought in contact with incandescent coal or coke, it is de- 

 prived of its oxygen, which unites with the carbon, forming carbonic oxide, and 

 the hydrogen is liberated. If the mixture of these two gases is brought in con- 

 tact with the vapor of naphtha it acquires illuminating properties, and is the il- 

 luminating gas which is now manufactured on such an extensive scale in New 

 York and many other large cities. 



The first successful attempt to manufacture this gas was made by Michael 

 Donovan, who obtained a patent for his process in 1830. Soon after, Jobard, a 

 Belgian, obtained a patent. Then followed Selligue, Lowe, and others. 



The process in most general use now is named after its inventor, Tessie du 

 Motay, and is the one employed by the Municipal and New York gaslight com- 

 panies in New York City. The operation is conducted as follows : — 



The gasogens in which the water gas is generated are arranged in pairs along 

 the main pipe, which passes through the center of the building. These gasogens 

 consist of vertical furnaces, constructed of iron and lined with fire brick, and 

 have a capacity of about ten tons of coal. In the lower portion on each side is a 

 row of doors for the removal of cinders; on the top are two large openings for the 

 introduction of coal, and a standpipe, which not only extends over to the main 

 pipe, but has a vertical extension, the end of which can be opened or closed by 

 means of a lid. 



