moment when this warning shall be given may be regulated at will, but with the ordinary adjustment the apparatus is supplied so regulated that the whistle will sound when the air supply is within fifteen to twenty minutes of exhaustion.     The respiratory mask with its crest resembles a fireman’s helmet extended downward mid forward so as to inclose the face completely. It is strong enough to protect the wearer’s head from blows or falls of hard substances. The respirable air contained within the helmet is isolated from the external atmosphere by means of a pneumatic tube which can be inflated at will and which, adjusting itself to every contour of the face, assures most absolute safety so far as air tightness is concerned, while it avoids all harshness of contact.     The discharge valve for the exhaled air is proof against any derangement. It consists of a simple membrane with large surface.—Engineering Magazine. From—Aberdeen Herald. (Aberdeen, Chehalis County, W.T.), 16 July 1908. Chronicling America: Historic American Newspapers. Lib. of Congress.