388 



SCIENCE 



[N. S. Vol. XXV. No. 636 



implements, their various uses ; the different 

 methods of hafting and the processes em- 

 ployed in their manufacture. The stone age 

 in Europe is treated at length, with descrip- 

 tions of the implements characteristic of dif- 

 ferent periods and the arts and manner of life 

 of the men who used them. There are chap- 

 ters on the Age of Copper and Bronze, The 

 Early Iron Age and Stone and the Metals 

 Outside Europe. Also there is a glossary of 

 terms and a list of hooks and papers dealing 

 with man's progress from stone to iron. 



SOCIETIES AND ACADEMIES 



THE AMERICAN CHEMICAL SOCIETY. 

 NORTHEASTERN SECTION 



The seventy-fourth regular meeting of the 

 Northeastern Section of the American Chem- 

 ical Society was held in the Lowell Building 

 of the Massachusetts Institute of Technology, 

 on Friday, February 15, with President L. A. 

 Olney in the chair. About seventy-five mem- 

 bers were present. 



Dr. David T. Day, of the United States 

 Geological Survey at Washington, D. C, ad- 

 dressed the section upon ' The Conditions of 

 Occurrence of Platinum.' 



The speaker began with a reference to the 

 remarkable increase in price of platinum — 

 about tenfold increase within the last four or 

 five years; this is not due to largely increased 

 demands, but has been brought about mainly 

 through the combination of large dealers and 

 hoarding of the metal by merchants and others. 



Platinum is always obtained by placer 

 mining, and deposits of value are known to 

 exist in the United States of Colombia, near 

 Choco Bay, but the climatic conditions, and 

 complications caused by government restric- 

 tions, render it impracticable to expect an im- 

 mediate development of the deposits. Plati- 

 num was discovered on the Pacific coast of the 

 United States at Pillar Point in 1850, but 

 being much more difiicult to recover from the 

 sands, than is gold, in ordinary placer mining, 

 development of these deposits was slow. De- 

 posits have also been located in California in 

 Ute County, along the Trinity River, at Mon- 

 terey, and on the beach at Santa Barbara; 



beach deposits occur on the coast of Oregon 

 and Washington; in British Columbia along 

 the Tulameen Eiver, is a valuable deposit well 

 situated for placer mining. 



Platinima occurs as an arsenide, sperrylite 

 in many sulphide ores, such as those at Sud- 

 bury, Ontario. It also occurs native with 

 gold, magnetite, chromite, serpentine and other 

 minerals in the black sands; here it is in ex- 

 tremely fine grains, as a rule, but the char- 

 acter of the deposit can be easily distinguished 

 by the microscopical appearance of the grains. 

 The modern methods of concentrating the 

 sands have now made a sure supply and no 

 real famine of platinum exists; but no good 

 substitute for it has yet been found in the 

 connections of the incandescent light bulbs, 

 nor, indeed, in any other industry. The pres- 

 ent supply of the metal is probably 100,000 

 ounces per year, and the probable future de- 

 mand is estimated at 200,000 ounces per year. 

 If worked systematically, the known placer 

 deposits could now supply 175,000 ounces with- 

 out drawing on the sulphide or arsenide de- 

 posits, and it seems unlikely that these ores 

 will be worked until the placer deposits are 

 exhausted. Several valuable by-products are 

 now being thrown away after the gold is taken 

 out of the black sand; the magnetite content 

 probably averages twelve per cent, and this is 

 capable of yielding excellent iron and steel by 

 smelting in the electric furnace. 



The lecture was illustrated with lantern 

 slides. In the discussion it was brought out 

 that the value of the platinum in the black 

 sands ranged from ten to fifty cents per ton. 

 Professor Robert H. Richards contributed to 

 the discussion a description of the black sands 

 and the method of concentrating and collect- 

 ing the fine platinum. The ordinary fire assay 

 is practically useless where the value runs less 

 than twenty cents per ton. But with the 

 Wilfley table and magnetic separators, fol- 

 lowed by an amalgamation process with mer- 

 cury containing considerable sodium, the 

 platinum and gold can be recovered. On re- 

 moving the sodium by treatment with water, 

 the platinum is practically all thrown down, 

 leaving the gold behind in the amalgam. The 



