336 



THE WORLD'S ADVANCE 



coins are now ready to be placed in cir- 

 culation. 



Although the coins minted at the Ex- 

 position model mint are not actual money 

 but silver and copper souvenirs com- 

 memorating the completion of the Canal, 

 yet they are made with the same care, 

 methods and machinery as are found in 

 five Government mints. 



Besides the mint exhibit itself there 

 is a supplementary display showing a 

 complete and very valuable collection of 

 all the coins issued at various times from 

 the mints. The variety of these coins 

 and the widely different designs in use 

 during the various periods of the nation's 



history, make the exhibit an interesting 

 one. A full set of the many medals that 

 from time to time are awarded by Con- 

 gress or other branches of the Govern- 

 ment is also shown. These medals, which 

 range in composition from bronze to gold, 

 are all made at the several Government 

 mints. 



Another relic of rather unique interest 

 is a crude iron hand press which was the 

 first implement used in the coining of 

 American currency. This press was in 

 operation at Philadelphia for some years 

 and with it were struck coins of various 

 denominations until in 1793 it was super- 

 seded by more efficient equipment. 



NEW SYSTEM OF LAWN SPRIN- 

 KLING 



A new system of lawn sprinkling in 

 the Los Angeles parks has been installed 

 and has already proven a great time and 

 money ' saver. 

 Water pipes 

 are buried in 

 the new lawns, 

 connecting 

 with sprinklers 

 spaced a few 

 feet apart so 

 that when the 

 water is turned 

 on t h e whole 

 lawn can be 

 watered at one 

 time. In this 

 way the water- 

 ing for a very 

 large park can 

 be attended to by one man. 



A System of Lawn Spraying Which is Permanent: The 



Water is Fed to the Nozzles Through Pipes Buried Beneath 



the Grass. 



It has the with great rapidity. 



Both receiver and transmitter can be 

 carried in a vest pocket ; in fact, they are 

 no larger than a watch. The cost of 

 manufacture is estimated at about thirty 

 cents. In the thermaphone there are no 

 magnets and diaphragm as in the tele- 

 phone, but in- 

 stead there is 

 a loop of very 

 fine platinum 

 wire within a 

 small alumi- 

 num cover 

 pierced with 

 minute holes. 

 Electric c u r- 

 rents passing 

 through the 

 wire cause 

 changes in 

 temperature al- 

 ternating from 

 hot to cold 

 The resulting ex- 



further advantage of sprinkling a lawn pansion and contraction of the surround- 

 more evenly than is possible by older ing air becomes evident as sound. 



methods - The great advantage of the therma- 



phone, aside from compactness and 

 cheapness, is its wonderful clearness of 

 enunciation. There is no confusion of 

 vowel sounds, letters or figures. The re- 

 ceiver is not more than an inch long, and 

 no thicker than a lead pencil, so that it 

 may be placed in the ear. This permits 

 the use of a double receiver while the 

 hands are left free to take notes. 



MINUTE TELEPHONE RECEIVER 



The thermaphone, an improved vest 

 pocket edition of the telephone, is the 

 recent invention of P. de Lange, of 

 Holland. The United States Consul at 

 Amsterdam, Mr. D. I. Murphy, used the 

 contrivance and vouches for the in- 

 ventor's claims. 



