INDUSTRIAL PROGRESS DURING THE YEAR 1875. cclxxix 



has introduced the novelty of an enameled water-pipe, 

 which they now manufacture of all sizes from one eighth of 

 an inch to sixteen inches in diameter. It is claimed for this 

 iron coating that it has been subjected to the most severe 

 chemical tests successfully ; that it will protect the metal ef- 

 fectually from rust or corrosion by acids; and that it is indif- 

 ferent to the action of heat and cold, boiling water, etc. For 

 domestic water supply, it would appear to possess decided 

 merits. In addition to our allusion to the discovery of the 

 great ore-body (or bonanza) on the Comstock lode, it is of 

 interest to mention the opening of a mine yielding gold, sil- 

 ver, copper, and lead near the town of Newbury, Essex 

 County, Massachusetts. Several shafts are down, meeting 

 an abundance of ore, much of which is of high grade. 



As the space at our command is limited, we may add, in 

 conclusion, it has been necessary, in our general resume, to 

 curtail our remarks upon many important topics, to simply 

 allude to others, and to omit all mention whatever of nume- 

 rous items of general interest. To a large extent, however, 

 this fault is remedied by the addition of the copious body 

 of descriptive items, which will be found under suitable clas- 

 sifications in another place. 



TECHNOLOGY. 



In the field of Chemical Technology we may record that 

 Kuhlmann has devised the following method of effecting the 

 regeneration of the manganese residues in the manufacture 

 of chlorine. 



The crude chloride of manganese solution is mixed with 

 chalk (in order to get rid of iron as a carbonate), and then 

 with milk of lime, to convert the chloride of manganese into 

 oxide. This oxide, after careful washing, is dissolved in 

 nitric acid, the solution evaporated, and the dry residuum 

 heated in retorts to a temperature sufficiently high to drive 

 off* the nitrogen as hyponitric acid and nitric oxide, but not 

 so high as to decompose the binoxide that will have been 

 formed. These vapors are led into and absorbed by the 

 hydrated oxide of manganese obtained as above detailed ; 

 the salt resulting is calcined, and the terminal stage of the 

 above - described operation gone through with it, and so 

 forth. In this manner the process of regeneration can be- 



