906 



Popular Science Monthly 



A simple telephone transmitter dragged through the 

 water reveals the nature of the river-bed 



Navigating a River Boat by Sound 



TO determine the character of inland 

 river beds, steamboat captains are 

 using microphones installed in sounding 

 leads. On each ship an armored cable 

 leads from the microphone to a telephone 

 receiver and dry batteries. When the 

 sounding-lead drags over the mud bot- 

 tom, a dull groaning sound emanates 

 from the receivers, while a stony or 

 pebbly bottom will cause a series of 

 sharp, staccato raps. 



triangular arm, or fan, which 

 rotates at a high speed, 

 throwing the water upward 

 against the dishes. 



After placing the trays 

 with their dishes in the ma- 

 chine, hot water is poured 

 in, the cover adjusted, and 

 the lever operated for two 

 minutes. The soiled water 

 is then drained ofif, fresh 

 boiling water applied, and 

 the operation repeated. The 

 dishes are thus washed and 

 sterilized. They dry of their 

 own accord if the water 

 is hot enough. Of course it 

 is well to scrape the dishes 

 reasonably clean before 

 putting them in the con- 

 tainer. 



The convenience of the machine may 

 be increased by a water-pipe connection 

 and a drainage pipe. Also a small motor 

 eliminates the use of the hand-lever in 

 operating the machine. 



Doing Away With the Dish- Cloth 



A DISHWASHER has been perfected 

 which does its work quickly and 

 well and which eliminates the unsanitary 

 dish-cloth. The machine consists of a 

 cylindrical container with a diameter of 

 about two feet, funnel-shaped at the 

 bottom and having a tightly-fitting cover 

 to prevent the escape of steam. A wire 

 tray with grooves holds the plates in an 

 upright position, and a central basket 

 contains knives, forks and spoons. After 

 being filled, the tray is placed in the bot- 

 tom of the container. Above it is 

 another tray for the teacups, water- 

 glasses and smaller dishes. Below both 

 trays, in the funnel-shaped bottom is a 



Washing and drying the dinner dishes 

 without a cloth and towel 



If you want further information about the subjects which are taken up in 

 the Popular Science Monthly, write to our Readers' Service Department. We 

 will gladly furnish, free of charge, names of manufacturers of devices described 

 and illustrated. 



