Popular Science Monthly 



929 



A Convenient Method of Handling 

 Dangerous Acids 



ACIDS are, at best, a nuisance to handle. 

 x\. The arrangement shown in the illus- 

 tration, however, solves the problem. The 

 original carboy of acid is ^^^^^ 



shown at A, and 5 is a ^ 



bottle with a stop-cock at 

 the base and a tightly 

 fitted two-hole rubber 

 stopper in the mouth. 

 The two are connected by 

 a glass tube C. The tube 

 passes from the bottle B 

 down through a loose 

 cover D placed on the car- 

 boy to keep out dust and 

 dirt. It should reach to 

 the bottom of the carboy 

 and be slightly bent at 

 the lower end to allow 

 the acid to flow out 

 freely. The short glass 

 tube in the bottle B, is 

 connected by rubber 

 tubing to an aspirator 

 or suction pump. 



Starting the suction 

 pump reduces the pressure in the bottle B, 

 and the acid is forced up into it by the 

 external pressure of the air upon the surface 

 of the acid in the carboy. Thus, the acid is 

 caught and held in a closed vessel, from 

 which it may be conveniently drawn off as 

 desired, without waste or danger. No in- 

 jurious fumes escape into the room and 

 there is no possibility of burns being 

 received from splashing, as the containers 

 are not moved until they are empty. The 

 acid is kept clean also. 



removed 

 carboys 

 suction 



Fine Aluminum Filings Make a 

 Violent Explosive 



THAT aluminum filings, made Into a 

 fine powder, form parts of two of the 

 most destructive agents is little known. 

 It has been used in the Austrian shells as 

 a component of the high explosive agent. 

 This explosive is known as ammonal, a 

 rnixture of five or eight parts ammonium 

 nitrate and one part of finely powdered 

 aluminum. Its explosive violence ig tre- 

 mendous. It is one of the few explosives 

 that have never been used as propellants. 

 No gun known to warfare could resist its 

 suddenness. For this reason it is used only 

 in projectiles. 



Uncleanliness the Trouble-Maker 

 for the Vulcanizer 



REPAIRMEN are often puzzled when a 

 . tire taken from one mold looks better 

 than one cured at the same time in another 

 mold. Both operations may have been 

 performed in the same way, yet the results 

 were different. 



A dusty finger print, drop of moisture, a 

 little oil from a tool, an insufficiently ce- 

 mented spot at the edge of a patch, a tiny 

 smooth space missed by the buffer — any 

 one of these may have caused the difference. 



Cleanliness and carefulness are always 

 the first requisites for successful results, 

 and the repairman who always inspects his 

 work carefully after each operation, is the 

 most likely to find the little trouble-makers 

 before it is too late. 



A Screen Door with a Special 

 Exit for Flies 



THE fact that a fly will walk over the 

 entire surface of a screen sometimes 

 trying to get out, led to the experiment 

 which resulted in the exit attachment 

 shown in the sketch. An ordinary screen 

 was used in its construction and an outlet 

 formed 6 in. from the top. The screen was 

 placed in the window with the exit-opening 

 pointing outward so that the fly in his 

 travels would walk out. The screen is cut 

 and a V-shaped extension applied. The 

 small end has an opening large enough for 

 the fly to pass out easily. 



The projecting part shown at the top allows 

 the flies to pass out but they cannot return 



This device is valuable because it allows 

 the flies within a room to escape and pre- 

 vents their return. — C. H. Thomas. 



