The Prescott daily news., 1918-04-26


 of the country how to perform the devices which, through electrical pre- cipitation, not only reclaim vast wealth from the smoke, dust and fumes of smelters and other plants, but at the same time redeem thou sands of acres of nearby land. AS matter of fact. the curb which he has put upon the smoke and dust nuisance his original aim-now actually bids fair to be, in some directions, the pri- mary reason for the running of certain of our industries. The smoke wizard who has accomplished these remark able things is Dr. Frederick c. Cot 'trell, chief metallurgist of the bureau of mines.
 Doctor Cottrelis experiments began several years ago when, as member of the staff of the University of Cal ffornia, he was called upon to solve the problem of helping a shelter locat- ed on San Francisco bay. The waste gases and vapors from this smelter, re- sulting from the sulphuric acid part ing process used in treating gold and silver bullion, were declared a nuis- nnce by neighboring farmers and seemed likely to provoke costly liti- gation and possibly lead to a shut down of the plant.
 The gases discharged into the air amounted to substantially 5000 cubic feet per minute and held in suspension an important proportion of sulphuric acid in the form of a fine mist. The corrosive action of the sulphuric acid was shown throughout the entire zone swept broadcast by the shifting winds. and both the agricuturists and the people generally had ample reason for complaint. The shelter was profit able one and the management was anxious to find some way to abate q nuisance that was both a menace to health and hurtful to vegetation.
 Laboratory Meets Industry.
 Doctor Cottrell's preliminary work brought up some puzzling situations. Up to certain stage matters went well enough on the miniature scale of the investigational tests, but be- yond this was the question of meeting the practical situation presented by q large commercial smelter. A big part of Doctor Cottrell's achievement lay in spanning the gap between the la boratory and tie industrial plant and in finding ways to control the enorm- ous pressures If the necessary cleo tric current, mounting up to 100000 volts.
 The problem vas solved, however and so well was. the precipitatOr in stalled at this smelter designed that it has been doing its work satisfactor- fly ever since. Further, by mere chance Doctor Cottrell attacked at that plant what is commonly admitted to be the most difficult of all problems of smoke or fume abatement, viz, the precipitation of acid mist.
 The good results obtained in this first instance soon became widely known and new line of application was opened a few years later when the great copper smelter at Balaklala. Cal. was threatened with fume litigation by the United States forestry service. ''Fume." or fine particles in the form of smoke, and sulphur dioxide gas, invisible to the eye, given off from the stacks of the shelter had swept the neighboring country bare of vegetation for miles, and it was case of either shutdown or suppression of these destructive discharges.
 A full-slzed plant of the Cottrell type was, accordingly, installed The volume of the gases treated averaged