K. DOMESTIC AND HOUSEHOLD ECONOMY. 441 



K. DOMESTIC AND HOUSEHOLD ECONOMY. 



TRANSPARENT SOAP. 



The most essential condition in the preparation of trans- 

 parent soap, and one frequently overlooked, is that the soap 

 employed shall be as nearly neutral as possible, as any free 

 fatty acid present separates subsequently in clouds and 

 flakes; while free soda, on the other hand, attracts carbonic 

 acid from the air, forming crystals of carbonate of soda. 

 The transparency of glycerin soap is also said to be im- 

 proved by the addition of a small quantity of white sirup. 

 15 C, XII., 191. 



THE USE OF GAS FOR LIGHT-HOUSES. 



The great advantage of employing gas for light -house 

 purposes is stated to consist in the fact that, by a very sim- 

 ple arrangement, the number of burners and the brill- 

 iancy of the flame can be increased from its ordinary to an 

 extraordinary brightness, such as to provide for its visibil- 

 ity in all kinds of thick weather, except, of course, that con- 

 dition of fog which no light, not even the sunlight, can pen- 

 etrate. In a fixed light apparatus, of any size, there is no 

 occasion to alter the existing lenses if we wish to introduce 

 the use of gas instead of oil; but in some lanterns it may be 

 necessary to provide for additional ventilation. The cost 

 of gas-light is said to be less than that of oil, while the pho- 

 tometric value of the flame of gas is largely superior to that 

 of any kind of oil. When the "fog-power" of the gas-light 

 is turned on, the cost of the gas per hour is greater; but 

 taking the average of a year's consumption, at several light- 

 houses, it appears that there is an actual saving of about 

 8300 per year by the use of gas. A very simple apparatus 

 effects an automatic intermission in the light, which not only 

 saves somewhat in the consumption of gas, but acts as a 

 means of distinguishing one light-house from another, pre- 

 cisely as is at present brought about by the introduction of 

 the flashing system. A gas-light of the first order, employ- 

 ing Mr. Wigham's gas-burners of 108 jets, would, if fixed, be 



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