Page:Popular Science Monthly Volume 91.djvu/141

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Popular Science Monthly

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��whatever the source, the light must be very strong. The exposure must be found by experiment, as it varies with the light, size of the lens, the subject photographed and

���The disk for holding the drop of water in lens barrel and the slide holder attachment

whether or not a color screen is used. The accompanying photographs show the fin- ished instrument and several of its photo- micrographs.

Very convenient slides may be made by cutting old lantern plates the right size. Colored glass makes very good filters when they are needed. It is of course under- stood that some transparent objects, such as the white blood corpuscles, must be dyed before photographing in order to render them visible.

The magnification of this instrument ranges from 300 to 500 diameters, depend- ing upon the lens and bellows extension. I have successfully examined and photo- graphed blood corpuscles, the starch cells in a potato and various other things by this method. On one occasion while using a magnification of 923.5 diameters the hair on a fly's leg appeared 2J/2 in- long. Another time, while ex- amining the wing of a recently killed fly I was able to see the watery fluid drying up in the capillaries. To perfect this

method several different instru- ments were tried out during more than a year of experi- menting.

The same method of con- structing a lens may be used in a similar manner for an ordinary microscope in cases of emer- gency, but the drop of water will need to be a trifle larger than for the camera lens. It can be made in a small loop twisted on the end of a small wire, allowing sufficient end for a handle.

��An Effective Fireproofing for Children's Clothing

IT is a common occurrence for children's clothing to take fire from playing with matches and from other causes. This may be prevented by a little precaution which may be taken every time the chil- dren's clothes are washed, particularly the dresses, suits and petticoats.

A non-inflammable solution of I oz. of alum or sal ammoniac should be added to the rinse water or starch. This renders the garments practically fireproof. Should they take fire, they would burn very slowly and without flame. — Jennie E. McCoy.

��Collecting Ants in a Sponge and Drowning Them

ANTS in the house or on the lawn can be quickly eradicated in the following way: Wet a large sponge and sift sugar all over it and place in the infested spot. It will be filled with ants in a very short time. Sink it in a pail of water and the ants will leave it and drown. Repeat the operation until they are all destroyed.

��Exterminating Moles and Gophers by Asphyxiation

IN some of the Western States moles and gophers are a great pest and difficult to exterminate. One of the best methods of getting rid of these animals is to fill their holes with the burnt gases from the ex- haust of a gasoline engine. The illustra- tion shows the method used by a Western farmer for the purpose. He attached a hose to the exhaust of an automobile

���Forcing mobile

��the deadly gases from the exhaust of the auto- engine into the burrows of moles and gophers

engine and forced the burnt gases into the burrows of the animals, causing death by asphyxiation.

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