VOL.8, NO.3
%7
DETERMINATION O F MOLECULAR WEIGHTS
small stoppered bulb and dropped on sand or glass wool in the bottom of the vaporization tube. The impact together with the increase in temperature drives the stopper out of the bulb and the substance vaporizes, driving out an equal volume of air which is collected in the pipet. The position of the leveling cylinder is now adjusted and the volume of the displaced air in the pipet is measured. Since the air is measured over water the pressure to which it is subjected is that of the atmosphere diminished by the vapor pressure of water a t the temperature of the room. Calculation of the molecular weight involves correction of the volume of displaced air to 0°C. and 760 mm. pressure and finding the mass of that volume of vapor which will occupy 22.4 liters a t O°C. and 760 mm. pressure. Convenient formulas for the calculation are given by Bigelow (I),Walker ( 2 ) , and Getman (3). Typical Determination of the Molecular Weight of Benzene (C&) 0.0228 0.0202 0.0148
7.45 6.68 4.90
20
742.8 Corrected 725.4
77.1 76.2 76.1
Av.
78.05
7 E
Literature Cited "Theoretical and Physical Chemistry," The Century Co., New York (. 1.) BIGELOW, City, 1912, p. 165. (2) W ALKER , "Introduction to Physical Chemistry." Sixth edition. The Macmillan Co., Ncw York City, 1910, p. 198. "Outlin~sof Theoretical Chemistry." Fourth edition, John Wile? and (3) GETMAN, Sons, New York City. 1927, p. 3 5
Ultra-Violet Light for Carbon Monoxide Poisoning. A new method of treating carbon monoxide poisoning with ultra-violet rays brings quicker relief to the patient than ordinary methods of treatment, according to results of a test reported by Dr. Koza of Pressburg. Carbon monoxide produces its poisonous effect by combining with the hemoglobin of the blood, displacing the oxygen which the body's tissues need and which they get from the blood. Some Italian observers had already found that when hlood hemoglobin, which was combined with carbon monoxide, was irradiated with ultra-violet light, the carbon monoxide disappeared in from thirty to sixty minutes. Dr. Koza worked. an the theory that a considerable part of the hlood is in the small blood vessels of the skin. Massage of the skin would stimulate the circulation in these blood vessels and let the ultra-violet rays go deep enough to reach the blood and driveout thecarbon monoxide. He tried this method on two sisters who were brought to the hospital hecause of carbon monoxide poisoning. One sister was treated by the new method, the other by the usual methods for overcoming carbon monoxide poisoning. At the end of forty minutes the first sister had lost half the deadly gas from her blood but the other sister had lost only one-quarter of it. The first sister regained consciousness after nine hours, the second after eighteen hours.-Srience Sewice
