Popular Science Monthly 



731 



Eliminating the Periscope from 

 the Submarine 



THE terror of the German U-boats 

 may be increased greatly since they 

 have been constructed without peri- 

 scopes. The sighting of the periscopes 

 has saved many ships from destruc- 

 tion. Without a periscope the sub- 

 marine may approach unseen. The 

 new German submarines are built with 

 two lenses, one on either side of the 

 boat, co-acting with other lenses and 

 reflectors. The disadvantage of this 

 method of constructing submarines 

 is that the boat must be much nearer 

 the surface of the water than it would 

 have to be with a periscope. 



A Medical Battery No Bigger Than 

 an Ordinary Flashlight 



MOST medical batteries are as large as 

 small-size suitcases and are therefore 

 difficult to carry about. The battery illus- 

 trated is no bigger than a flashlight, yet it 

 gives sufficient current to afford a shock and 

 operate the vibrator. A miniature 

 battery is provided in one of the han- 

 dles or containers, and in the 

 other are carried the switch, the 

 starter, the pin which regu- 

 lates the current and the 

 vibrator. 



This type of battery will 

 be found useful for mas- 

 sage and wherever slight 

 electrical stimulation is re- 

 quired. 



It takes up very little 

 space in the physician's 

 hand-bag; or it can be car- 

 ried in the pocket without 

 inconvenience. 



The pollen of the orchid is blown against the 

 wires, and is held there and nourished by the dust 



Orchids That Grow on Telegraph 

 Wires Over the Streets 



IN Porto Rico it is not unusual to have an 

 orchid garden hanging over your house, 

 suspended from telegraph wires. So heavy 

 do the wires become when supporting the 

 plants that it frequently becomes necessary 

 for the telegraph companies to have 

 them scraped to remove the growth. 

 Tropical orchids usually cling 

 to the trunks or branches of 

 large trees or ferns, where 

 they produce aerial roots 

 which absorb moisture from 

 the atmosphere. Some are 

 climbers and others grow 

 head downwards. One 

 very beautiful species grows 

 in moss. 

 The one thing necessary 

 for them is abundance of air. 

 The plants shown in the pho- 

 tograph above are evidently 

 satisfied with their supply. 



Vibrator control 



chfor 



Spong 



The miniature 

 battery gives 

 sufficient cur- 

 rent to operate 

 the vibrator 



Details of the 

 battery showing 

 the complete- 

 ness of its equip- 

 ment for medi- 

 cal purposes 



Regulating switch 



Why Anthracite Coal Lands 

 Differ in Price 



THE prices of anthracite coal 

 lands vary from $200 to 

 $1,000 an acre, the smallervalues 

 being for lands containing rela- 

 tively thin coal or practically 

 exhausted veins. The medium 

 values are paid for relatively 

 small, unopened areas. The ex- 

 treme values are for going con- 

 cerns or for lands so located 

 strategically that they have a 

 special value for the purchaser. 



