792 POPULAR SCIENCE MONTHLY. 



They found an average net yield of acetylene of 4'926 cuMc 

 feet of moist gas per pound of net carbide, or 4*696 cubic feet per 

 pound of gross carbide. A gross ton of carbide, then, will yield 

 about 9,400 cubic feet of acetylene at a cost very slightly above 

 $32.76, as the final formation of acetylene is practically without 

 expense. Nine thousand four hundred cubic feet of coal or water 

 gas costs the consumer somewhere between fourteen and sixteen 

 dollars, roughly about one half as much as the same amount of 

 acetylene. But as acetylene gives over eight times as much light 

 per cubic foot, a large margin seems to be left for decreased gas 

 bills to the consumer and increased profit for the producer. On 

 the whole, then, it may be said that acetylene promises to be an 

 important rival of the present methods of illumination, and de- 

 serves the careful examination of both the consumer and manu- 

 facturer of light-givers. 



It has been proposed to use calcium carbide as a concentrated 

 fuel on war vessels and in places where space is of more impor- 

 tance than cost. Dr. Frank has made the following calculation 

 of the gain in space over coal : To provide power for a one-thou- 

 sand-horse marine engine for twenty-five days would require four 

 hundred and thirteen tons of coal, occupying a space of about 

 fifteen hundred cubic feet. In this space could be stored enough 

 of the carbide to propel the ship at the same rate for seventy-five 

 days. In other words, as a fuel one ton of carbide is equal to 

 three tons of coal. There are works engaged in the manufacture 

 of calcium carbide at Spray, N. C, at Niagara Falls and at Lock- 

 port, N. Y. ; in Europe, at Betterfeld, Prussia, at Neuhausen, 

 Switzerland, at Baden, in Germany, and at Troyes and Val- 

 lorbes, in France. 



The native Micronesian population of the Marshall Islands is repre- 

 sented by Dr. Steinbach to be rather increasing than decreasing — a census 

 on one of the islands showing an increase of about fifteen per thousand a 

 year. The density is about sixty-eight to the mile. The people are divided 

 into four sharply defined classes : the common people, or Kayur ; the next 

 higher class, the Leataketalc, comparable with the village magistrates in 

 Germany, who see that the orders of the chief are carried out ; the ordi- 

 nary chiefs, Burak ; and the Iroj, or head chiefs. Neither of the two lower 

 classes own land, but they are allowed to grow as much produce or catch 

 as much fish as is necessary for their sustenance ; and they have to pei*- 

 form certain services for the chiefs. The ordinary chiefs often possess 

 larger holdings than the Iroj, or head chiefs. All the members of the four 

 classes acquire their rank through the mother only. The son of a woman 

 of the Iroj class is always an Iroj, even though the father be a common 

 Kayur. The chiefs have still considerable dignity and power, including 

 that of life and death. 



