Page:Popular Science Monthly Volume 91.djvu/719

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�Popular Science Monthly Transporting a Precious Mirror Up

a Mountain by Motor-Truck j^Mf 4

THE hope of astronomers the world over, the largest tele- scopic mirror in existence, one hun- dred inches in diameter and worth over one hundred thousand dol- lars, was recently safely trans- ported up the winding nine and one-half mile trail from Pasa-' dena, Cal., to the top of Mount Wilson, by motor-truck. It is said to be the most expensive load ever carried by a motor-truck and its safe arrival at the top, one of the great- est feats contri- buted to" science by the motor- truck.

The mirror is priceless, since it cannot now be duplicated, and is ground so accu- rately that its surface changes

from the heat of a man's body three feet away. For this reason, it was carried on the truck in a special air-tight box lined with paraffin, with layers of carded wool to protect it against breakage and to maintain it at an even temperature. In turn, the box itself was mounted on powerful but delicately-adjusted coil springs to prevent any possibility of breakage due to the uneven road surface up the steep trail. The trail has fifty turns in it with an uphill grade of not less than twelve per cent at any point.

A special brakeman on the truck did nothing but apply the brakes so that the driver might give all his attention to steering.

Another man on the top of the truck, gave his entire at- tention to the cov- erings and strappings around the precious load. Still another walked behind the truck in order to observe the least tendency of any

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��The truck in which the 100,000-dollar mirror was carried up the mountain- At left is shown the details of the construction

��part of the load to slip or become dis- arranged. The trip was made slowly, so that the man walking behind had no difficulty in keeping up with the truck.

���The paper strips are fastened one on each side of the cover to keep the holder in place

��Keeping Your Pencil Where You Can Find It

STENOGRAPHERS and scribes of every description will appreciate this new pencil - holder, invented by George W. Paulus, of Grand Rapids, Mich., which can be at- tached to any kind of a note-book. It is in the form of an open-sided cylinder, of a diameter about equal to that of an ordinary pencil. At the back of the cylinder is a bead extending the full length of the device. This serves the double purpose of strengthening the holder and of provid- ing a means for affixing a stiff piece of paper to it. The paper is used to glue the pencil-holding device to the cover of the pad.

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