DIRECTIONS FOR USING THE SIMPLEX SPIROMETER. Hang the Spirometer upon a hook securely to the wall about the height of the shoulders and situated so as not to come into contact with doors or movable furniture. Thoroughly ventilate the room and allow the entrance of all the fresh air possible, weather permitting, in order that the lungs may be ventilated and the exercises invigorating. Remove all clothing that tends to bind chest, waist or abdomen from expanding freely;—belts and corsets especially must be laid aside. Keep the shoulders turned backwards and be careful not to raise the shoulder blades or collar bone, keeping all the muscles flexible. At each test, have the hand point to the figure “0” turning it to the right or left by means of the nickeled hub. AVERAGE LUNG CAPACITIES. Height 5 feet 180 cubic inches “ 5 2 inches 185 “ “ “ 5 4 190 “ “ “ 5 6 195 “ “ “ 5 8 205 “ “ “ 5 10 215 “ “ “ 6 feet 230 “ “