K. DOMESTIC AND HOUSEHOLD ECONOMY. 411 



K. DOMESTIC AND HOUSEHOLD ECONOMY. 



THE CONSTKUCTION OF WINDING STAIRCASES. 



In Major Elliott's Report on European Lighthouses, he notes 

 that in several cases the stairs are circular, and apparently 

 self-supporting, one end only being built into the wall, as in 

 the Treasury at Washington. This method of stair-building 

 is, he observes, universal in Europe, both in private and public 

 buildincrs. The most recent lio-hthouse towers of the Ameri- 

 can system are constructed with conical interior walls and iron 

 staircases winding around the interior of the cone. European 

 towers are generally constructed with an exterior conical, and 

 an interior cylindrical wall, leaving an unnecessarily large 

 unused space between the two. The amount of masonry in 

 the American system is the same as in the European, and 

 is better calculated to resist the overturninof effect of the se- 

 verest gales. Elliott'' s European Lighthouse System^ p. 25. 



SELF-CLOSING HINGE FOR STORM-DOORS, DOUBLE DOORS, ETC. 



A very ingenious self-acting hinge lor storm-doors, double 

 doors, etc., opening in one or both directions, has been de- 

 vised by Koch, of Berlin. It is said to allow the door to 

 move easily and noiselessly, and also to be fixed at an angle 

 of a little more than ninety degrees, if desired, without any 

 fastening. A full description, however, can only be given 

 with the aid of a figure. The door moves on a pivot at the 

 top and bottom, the rear end at the bottom resting in a shoe, 

 to which it is firmly screwed, and Avhich has the pivot at- 

 tached to it beneath, and also a small wheel a little in front 

 of the pivot. As the door is opened this small wheel moves 

 upon an arm of a lever, the other arm of which is in contact 

 with the end of an almost circular horizontal spring, which 

 carries the door back to its normal position, as soon as it is 

 released, the power being greatest just when the door is re- 

 leased, and diminishing until it is completely closed. The 

 spring, lever, etc., are inclosed in a cast-iron box, covered 

 with a brass plate, screwed to it, countersunk to the level 

 of the flooi*. The upper socket, set in the casing of the door, 



