384 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



resin as it is driven in. Chairs, tables, lounges, etc., are con- 

 tinually getting out of order in every house, and the proper 

 time to repair them is when first noticed. The matter grows 

 worse by neglect, and finally results in laying aside the article 

 as worthless. If screws are driven into wood for a temporary 

 purpose, they can be removed more easily if dipped in oil be- 

 fore being inserted. 3 A, May 27, 383. 



TIGHTENING CURTAIN-CORD. 



The following method is recommended for tightening the 

 endless cord used in window-blinds : Let the pulley over 

 which the cord passes be mounted on one arm of an L-shaped 

 slide, the other arm passing inside a heliacal spring, the whole 

 mounted in a slotted tubular case, which is to be fastened to 

 the window-casing, or other place, so that the heliacal spring 

 acts upon the pulley, to keep the endless cord at the tension 

 necessary to act upon the curtain-roller, and the spring yields 

 to any contraction or expansion of the cords under atmos- 

 pheric changes. The arm of the pulley-slide, being within 

 the spring, can not become obstructed in its movement in the 

 tubular case. Student, February , 1870, 107. 



PROTECTING CORKS AGAINST ACIDS. 



Corks may be protected from the action of acids by first 

 soaking them for several hours in a mixture of one part con- 

 centrated water-glass and three parts water. The corks are 

 then allowed to dry, and afterwards coated with a mixture 

 of finely-powdered glass and water-glass. When this coat- 

 ing is dry, the corks are to be placed for a short time in a 

 solution of chloride of calcium, from which they are removed 

 at length and washed with water, and dried. 8 (7, 1870, 15. 



PREPARATION OF COURT-PLASTER. 



Our readers may thank us for a method of preparing what 

 is asserted to be an excellent quality of court-plaster, fully 

 equal to that usually sold in the drug-stores. For this pur- 

 pose, bruised isinglass is soaked twenty-four hours in a little 

 warm water. Nearly all the water is then to be evaporated 

 by a gentle heat, and the residue dissolved in a small quanti- 

 ty of proof spirits, and the whole strained through a piece of 

 open linen. The strained mass should be stiffened jelly when 



