66 



THE WORLD'S ADVANCE 



of the fire may be readily determined 

 and the necessary action taken to pre- 

 vent it from spreading. The observation 

 stations are also equipped with a field- 

 glass, a heliograph which serves as an 

 auxiliary to the telephone, and a portable 

 telephone. The last named may be put 

 into commission by merely grounding 

 one terminal and connecting the other 

 to the main telephone line. 



The fire-fighting tool box, a cylindrical, 

 galvanized-iron object, next attracts the 

 visitor's attention. It is about six feet 

 high by three feet in diameter and ac- 

 cess to the interior is by means of a 

 hinged door built into the side. These 

 receptacles are painted red and, together 

 with weather-proof iron-box telephones, 

 are placed along the routes of travel fol- 

 lowed by patrolmen and campers. The 

 equipment of the fire-fighting tool box 

 consists of several axes, saws, picks, 

 rakes and shovels; a lantern, a kerosene 

 torch for backfiring, a carbide light for 

 fighting after dark, water-bags and a 

 compact set of cooking utensils for four 

 men. 



The following six golden rules for fire 

 prevention are posted conspicuously 

 about the exhibit: (i) Be sure your 

 match is out. Break it into two before 

 you throw it away. (2) Don't throw 

 away burning tobacco. (3) Make your 

 campfire small and in a safe place. (4) 

 Put out your fire with water and then 

 cover it with earth. (5) Don't make 

 large bon-fires. (6) If you find a fire, 

 put it out; if it is too big, notify a 

 ranger. 



A novel exhibit in the Palace of Edu- 

 cation is that consisting of a huge relief 

 map of the state of New York on which 

 are shown, by means of miniature elec- 

 tric lamps, the location and classification 

 of all the educational institutions in the 

 state. The map is approximately twenty- 

 five by thirty-five feet in size. Each 

 class of schools is represented by a cer- 

 tain color of lights and the various colors 

 flash on and off in definite order. The 

 elementary schools are represented by 

 12,138 white lamps, 496 of which are 

 huddled together in New York City. 

 Over fourteen thousand lamps are used 

 in the exhibit. 



The fire assay laboratory of the U. S. 



Bureau of Mines in the Palace of Mines 

 and Metallurgy is employed to demon- 

 strate the fire assay method of determin- 

 ing the value of gold and silver ores. 

 The ore to be tested is pulverized and 

 mixed with a flux (soda litharge borax) 

 which aids fusion. Granulated lead is 

 now added to the mixture, the whole is 

 placed in an earthenware crucible and 

 the latter with its contents is put into 

 an oil-burning furnace of the Braun- 

 Muffle type. Fusion takes place at about 

 1600 degrees F. and the liquid mass is 

 poured into a conical-shaped mould to 

 solidify. The slag, containing the waste 

 materials of the ore, rises to the top, 

 while the heavier lead settles to the bot- 

 tom, forming what is called the lead 

 button. Lead has a property of absorb- 

 ing gold and silver, when in a molten 

 state, and hence all the gold and silver 

 formerly contained in the pulverized ore 

 is now present in the lead button. The 

 slag is broken away from the button and 

 the latter is placed in a cupel and put into 

 the furnace where it attains a tempera- 

 ture slightly above the melting point of 

 lead. This cupel is made of a mixture 

 of bone ash and cement and has a prop- 

 erty of absorbing liquid lead at "red 

 heat," while gold and silver are not af- 

 fected. Thus the lead of the button is 

 oxidized, and absorbed by the material 

 of the cupel, and a small globule of gold 

 and silver remains. These two metals 

 are next separated by dissolving the sil- 

 ver in nitric acid. The final speck of 

 pure gold is placed on a balance having 

 a sensitivity of six millionths of one 

 ounce, and, by a comparison of its weight 

 with that of the pulverized ore tested, 

 the "run" of the ore is computed and 

 its value determined. 



He who is wandering about in the Pal- 

 ace of Liberal Arts will be attracted by 

 the sight of a monstrous typewriter. This 

 prodigious machine is 21 feet long by 15 

 feet wide and is, in detail, an exact re- 

 production of one of the standard type- 

 writers manufactured by the owners of 

 the exhibit. It is 1728 times larger than 

 the standard, weighs 14 tons and was 

 built at a cost of $100,000.00. The car- 

 riage weighs a ton and a half, the key 

 cups are seven inches in diameter and 

 the printed letters are three inches high. 



