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 



703 



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. 



