428 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ure of the air deposits, and is then carried off by a suitable 

 wooden gutter; the air of the cellar being thus always kept 

 dry. 5 C, IV., 1875, 31. 



KEPAIEING LEAKY CELLAR WALLS. 



The repairing of leaky cellar walls should never be delayed, 

 since the crevices are continually widened by the water soak- 

 inof throu2:h. Cement, tar, and water-o;lass are the best ma- 

 terials for the purpose, but the last two can only be used at 

 a time when the cellar is dry, as in winter, perhaps even in 

 September, or after drying and airing it in winter by artificial 

 means. When nearly dry the leaky portions of the wall can 

 readily be recognized, and should be marked with charcoal. 

 Holes and cracks should first be filled with hydraulic cement. 

 The marked places, when dry, should be coated three to four 

 times with a solution of one volume of commercial water- 

 glass in two of water, and finally, after becoming perfecth^ 

 dry, with a solution of one volume of water-glass in one half 

 a volume of water. Instead of the solutions of water-glass, 

 tar, kept quite liquid by heating, may be laid on a number of 

 times. If cement is to be employed, the marked portions of 

 the wall should be cut out wedge-shaped, and carefully filled 

 with a cement rather thickly made up with one third sand. 

 If the cellar can not be dried, the moist places should be cut 

 out somewhat deeper (four to six inches), and filled with ce- 

 ment, by placing a tube of any material, about as thick as 

 a finger, in the middle, and packing the cement in tightly 

 around it; and, if necessary, holding it in place with a board 

 until it hardens, while the water escapes through the tube 

 without exerting any pressure upon it. After twenty to 

 thirty days the opening may be plugged up. 8 C, XIL, 

 204. 



EXPLOSIONS IN FLOUR-MILLS. 



An explosion which took place, in 1872, in a flour-mill in 

 Glasgow, led to an examination of the subject by Dr. S. 

 McAdam, who, having discovered that similar ones had taken 

 place in Scottish flour-mills on previous occasions, has pre- 

 sented to the Royal Scottish Society of Arts, a thorough an- 

 alysis of the causes leading to these explosions. Most of the 

 improved modern mills employ what is called an exhaust 



