Page:Popular Science Monthly Volume 89.djvu/900

From Wikisource
Jump to navigation Jump to search
This page needs to be proofread.


��Popular Science Moni/ih/


��Why DofS Sap Rise in a Tree Against the Pull of Gravity ?

NOT every b( )tl y knows that solutions of two dilierent substan.'es placed on opposite sides of a membrane or a ])ulp make diligent efl'orts lo equalize their density.

For examjile, take a glass tube, cut off the lower end of a potato, and peel the remainder for about one-third of its length. Bore a one-inch hole through two-thirds of the potato and in the end fit a cork. Bend a glass tube into L-shajie, put vaseline on the short arm and insert it in a small hole bored in the side of the potato lo reach the big hole, l-'ill the interior of the potato with sugar colored with ink, fasten the cork and glass tubing tight. Place this apparatus in a dish of water. The water. Hows through the pulp of the potato and on reaching llu- iliin membrane separating it from the colored liquid it dilTiises more f|iiickl>' through the colored li(|uitl th latter docs through it, becii it is less diiise than th colored liquid. This causes the wa t e r to push the denser liquid upward into the tube. This action, together with ca- pillary attraction iswhat causes the sap to rise.

��A Time-Saving "Safety-First" Tool for Dynamite Workers




��An experiment with potatoes to illustrate the principle involved in the rising of sap in a tree

��M.\Ki: -SHIFT methods of crimp- ing tKiianiite caps and connecting the cap and fuse to the cartridge have led lo scores of severe accidents and many fatalities in land- clearing work. A com- liination tool, which will cut and slit the fuse, crimp the cajj on ihe fuse and finally punch clean- cut holes in the cartridge for the secure fastening of the cap anil fuse to the cartridgehasbeende\ised by \'. D. Li\ingston, land clearing tlemonstra- lor, Wisconsin t'ollege of Agriculture.

The arrangement for

slitting the end of the

fuse exposes a pocket of

powder which will ignite

quickly. The crimping

(IcN'ice at the center of

the tool dcK-s a neat job

antl a strong one. When

properly used to crimp a cap to the fuse,

il requires a twenty-five pound pull to

remove it. One of the handles has a

d eiul, designed for pimch-

thc holes in the dynamite

cartridge. The apjiaratus

is intended to saw time

as well as to insure the

safety of the workers.

A combinntion tool which will cut and slit the fuse, crimp the cap and punch dean holes in the cartridge

����� �