134 



SELECTION AND USE 



arrangement, designed, we believe, by Mr. Highley, and 

 figured in Beale's work on the microscope. It consists, as 

 shown in the engraving (see Fig. 31), of a bag or net of 

 some light material, to the bottom of which is attached, by 

 means of twine, or a strong rubber ring, a wide-mouthed bottle. 

 Any quantity of water may be poured into the bag, and all the 

 objects which it contains will roll down the sides of the bag 

 and fall into the bottle, while the fluid escapes through the 

 sides. Delicate objects are consequently not exposed to 

 pressure, rubbing, or any other violence, as they would be in 

 an ordinary filter or bag, and the whole affair is so simple that 

 any one can make it. 



A slight modification of this arrangement will be found ad- 

 mirably adapted to the microscopic examination of the water 

 supplied to cities. The bag may be attached to any faucet, and 

 and all the water that is used in the household may be caused 

 to pass through it. In this case, if the bag be made of some 

 tolerably stout material, it may be firmly tied to the faucet, 

 and then all the water that is consumed will be very thor- 

 oughly purified. 



Another very excellent device is the bottle invented by 

 Mr. Wright, of which a modified form is shown in Fig. 

 32. The mouth of the bottle is closed by means of a 

 cork in which two funnels are inserted. 

 One of these funnels is placed in the bot- 

 tle, mouth down; the other projects above 

 the cork, as shown in the engraving. The 

 mouth of the funnel that is in the bottle 

 is covered with muslin or flannel, held in 

 place by a rubber band, which is prevented 

 by a wire ring from slipping along the con- 

 ical surface of the funnel. When water 

 is poured into the other funnel, it passes 

 into the bottle until the latter is full, and 

 then it flows out of the first funnel, and 

 is carried off" by means of a short piece of 

 rubber tubing. Meanwhile, all solid parti- 

 cles are held back by the filter, and as the 

 latter is horizontal and with the filtering Fig. 32. 



