Popular Science Monthly 



87 



and subsequently patented her discovery. 

 So the story ran. Romantic, indeed — 

 but, like many another tale of the begin- 

 ning of some great enterprise, it lacked 

 the verification of fact. In reality, Mrs. 

 Everson was the wife of a doctor. She was 

 a good chemist and her discoveries were 

 the result of laborious experimentation. 



Potter and Delprat, though working 

 independently, devised a method also 

 involving the use of gas in adsorption. 

 During the next few years, the names of 

 Froment, Cattermole, Wolf, Elmore, De 

 Bavay, McQuiston and Bradford came 

 into prominence through their efforts in 

 improving upon the earlier methods of ore 

 concentration by flotation. 



But not until Sulman, Pickard and 

 Ballot had conjointly rubbed the miner's 

 lamp which evolved modern froth flota- 

 tion, did the colossal outlines of this djinn 

 of mining appear in its true significance. 



These men were experimenting with the 

 Cattermole process which used oil in the 

 proportion of from for- 

 ty to one hundred and 

 twenty pounds per ton 

 of ore. The oily metal- 

 lic particles collected 

 in clusters and then 

 sank from sheer weight. 

 The gangue was forced 

 upward by streams of 

 water and floated off. 

 These men decided to 

 see what would happen 

 if the quantity of oil 

 was reduced gradually 

 to the vanishing point. 



As the percentage of 

 oil was diminished, the 

 results became less and 

 less satisfactory, until 

 the process failed to 

 work at all. Then to 

 the amazement of the 

 experimenters, upon 

 stopping the agitation, 

 myriads of glistening, 

 dancing bubbles came 

 surging along the sur- 

 face of the liquid, 

 crowding each other in 

 their effort to reach 

 the top with their pre- 

 cious cargo of mineral 

 wealth. The oil had 



Western Newspai>er Union 



A weather vane made from bits 

 of metal by a soldier at the front 



entirely disappeared from sight and 

 touch. Investigation revealed the pres- 

 ence of the oil on the metal particles in a 

 very thin film. The bubbles were ex- 

 tremely small and persisted longer. 



At Broken Hill, Australia, where the 

 experiments were performed under the 

 supervision of Sulman, Pickard and 

 Ballot, there had accumulated about 

 12,000,000 tons of ore from which the 

 metals could not be recovered by the 

 ordinary methods. The weight of gangue 

 equalled that of the zinc and lead min- 

 erals present. Therefore, separation by 

 gravitation methods was out of the 

 question. While the CJattermole process 

 would recover a reasonably large percent- 

 age of these metals, the newly discovered 

 froth method gave unlooked-for success, 

 and has been widely used ever since. 



Is the Wind Right for Gas? Look 

 At the Trench Weather Vane 



THERE are weath- 

 er vanes galore in 

 the trenches and 

 throughout the fight- 

 ing area. Many of 

 them are ornamental in 

 design and plainly tes- 

 tify to the skilful fin- 

 gers and artistic tem- 

 perament of some of 

 the boys. The one 

 shown in the accom- 

 panying illustration 

 was made by a Cana- 

 dian soldier out of odds 

 and ends of metal. It 

 represents a cyclist and 

 answers to the slight- 

 est breath of wind. 



It is vitally impor- 

 tant that the soldier 

 know in what direction 

 the wind is blowing or 

 is likely to blow; for 

 if it is coming from 

 over the enemy's camp 

 there is danger of a gas 

 attack, and when the 

 gas starts over, he 

 has only from twenty 

 to forty seconds in 

 which to adjust his 

 gas mask. 



