Popular Science Monfhh/ 



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A New Garden Duster Which Uses 

 Dry Spray 



TIIIC iiso of dry s[)ra\s iiislcad of 

 liiiuiil poisons is roining into favor 

 ainonji gank-n niaicers because they in- 

 volve less work, are not so dirty and are 

 ready for instant use. A new hand 

 duster for aj^pKing dry sprays is novel in 

 principle as well as design and is by far 

 the most efficient de\"ice which has yet 

 been in\'cntcd. The powder is contained 

 in a large metal reservoir, within which 

 the pumj) mechanism acts. Kach mcne- 

 ment of the jiiston automatically meas- 

 ures and ejects an amount of dust regu- 

 lated b\' the force imparled to the jiiston. 

 It is double acting and will throw a cloud 

 of dust or powder up or down or in any 

 other direction. With this new duster 

 a single puff of arsenate of lead will com- 

 pletely co\er a potato plant with the 

 poison. All vegetables and small fruits 

 and even low trees may be quickly 

 sprayed with poison or with sulphur 

 with a minimum of effort. 



The duster may also be used as a 

 house disinfectant, discarding the arse- 

 nate of lead for a non-poisonous liquid 

 or powder. No corner is beyond reach 

 of the duster, and the acids used as 

 sprays do not injure it. 



How the Snail's Tongue Cleans the 

 Aquarium 



The liquid is forced into the recesses of 

 vegetables, small fruits and low trees 



The snail has a tongue which closely re- 

 sembles the teeth on a carpenter's rasp 



EVERY one who keeps an aquarium 

 knows that it is advisable to place 

 a few snails in the tank, not only be- 

 cause snails are interesting in themselves, 

 but because they are good cleaners. 

 If the keeper of the aquarium knows that 

 too much sunlight will produce too much 

 plant growth, and has placed the vessel 

 in a partly shaded place where the pro- 

 portion of light and shade is about right, 

 the snails, if they are numerous enough, 

 can then control the growth. They creep 

 along the side of the aquarium, as if they 

 were idling away their time and merely 

 crawling around to call on their neigh- 

 bors. In reality the\' are not dreamers 

 but scavengers. 



Nature hiis provided them with a 

 peculiar anatomical structure resem- 

 bling a narrow ribbon, which in detail is 

 like the band of teeth on a carpenter's 

 rasp, lender the microscope these so- 

 called "lingual ribbons" or tongues are 

 seen to be thickly set with rows of 

 sharp-edged teeth which arc themselves 

 lOfjthed and which rasp off microscopic 

 ])lants and carry them into the mouth. 



The accompanying illustration is from 

 a marine form known as the "blcoding- 

 teeth" snail. In the original the ribbon 

 has a bright reddish color as if it had 

 been dipped in blood. When the image 

 is thrown on the screen by the projection 

 microscope, it resembles a huge red rasp 

 three or four feet in diameter and extend- 

 ing across the entire width of the screen. 



