950 



Popular Science Monthly 



the 8-hour or normal rate. With the 3- 

 series, 8-paralIel battery the most con- 

 venient way is to charge it with bichromate 

 batteries. These cells are cheaply and 

 easily made of zinc and carbon scrap. They 

 have a potential of about 2 volts and are 

 high in amperage. Connect the two groups 

 of 5 in series and place the two groups in 

 parallel. Also connect the 8 units of 

 storage-battery in parallel and connect with 



TO AUDI ON 



^ OFF 



F)&7 

 When the storage-battery is used on an 

 audion it is necessary to supply an end switch 



the bichromate batteries. Be sure to con- 

 nect the zinc element of the bichromate 

 cells with the negative of the storage- 

 battery. This is shown in Fig. 5. This 

 method of connecting the storage cells in 

 parallel series is only for the purpose of 

 charging. When used on the discharge 

 they must be disconnected at the binding 

 posts and connected in series as in Fig. 6. 



The cells during the charge should give 

 off gas. Toward the end of the charge 

 they should gas freely. A failure to gas is 

 a sure sign something is wong. An insuffi- 

 cient voltage or a short circuit in some one 

 cell may be the trouble. When the negative 

 begins to gas freely, or when the electrolyte 

 turns to a milky color, it is a good sign that 

 the cells are charged. A slight overcharge 

 will do no harm. An overcharge is fre- 

 quently used to clean out the elements. 



The battery fully charged will give a 

 voltage of about 60 when connected in 

 series. To provide the most efficient volt- 

 age for an audion it is necessary to supply 

 an end cell switch, as shown in Fig. 7. 

 The voltage will soon drop to about 50 

 where it remains practically for the life 

 of the charge. Do not discharge to a 

 lower voltage than 42. A light charge 

 should be given every two weeks. 



A New Wireless Station on the 

 African Coast 



ANEW wireless station has been erected 

 on Cape Juby, on the African coast. 

 In cases of need at sea the service is avail- 

 able for ships in distress. As the installa- 

 tion on Teneriffe Island is less than 100 

 miles from the Cape Juby plant, communi- 

 cation with the Canary Islands is possible 

 and, through them, with the Spanish 

 mainland. 



Cape Juby is a sandy and practically 

 barren projection into the Atlantic Ocean 

 some 67 miles from the Island of Fuerteven- 

 tura of the Canary group, and in the same 

 latitude. It is a part of that section of the 

 western Sahara which extends along the 

 Atlantic coast and connects the Mogador 

 district with that of the Rio de Oro. The 

 last named was recognized as Spanish 

 territory by the treaty of Paris of 1900. 

 Water is very scarce on the cape, although 

 it can be obtained in the ravines by sinking 

 wells. The interior region is said to support 

 great numbers of sheep and to produce 

 excellent crops of wheat, barley and corn. 

 The ocean fisheries at this point are very 

 abundant. 



A Light Signal to Designate a 

 Blown Fuse 



WHERE there are a number of fuses on 

 one block and the block is placed in a 

 dark corner, a blown fuse is hard to locate 

 without a light or pocket flashlamp. To 

 eliminate the wiring for a lamp and have a 

 light ready to locatethe burned-out fuse the 

 arrangement shown was' installed. Each of 

 the fuse-cartridges in the block was 

 shunted through a low candlepower lamp. 

 Such a lamp will not affect the rating of a 



LAMP 



A low candlepower lamp glows when the 

 fuse is blown and until another is installed 



fuse to any extent and will not glow until 

 the fuse is blown. — Jessie C. Haskell. 



