USES OF PAPER CHROMATOGRAPHY 385 I with $ mi. distilled water, verifying that the solution is alkaline, then extract the essences and fatty emulsionants by shaking with 20 ml. ether oxide without peroxide, wash the ethereal layer with 5 ml. distilled water add to the ether 0.4 ml. ammonia. The ammonium salt of thioglycolic acid is precipitated. It is extracted with 1 ml. distilled water. The aqueous layer is used for the chromatography. Use solvent No. 7. Duration of chromatography. The duration is about 14 hours, the experi- ment being stopped when the column of liquid attains a height of 26 cm. Indicator MI. I 0.1-N silver nitrate 50 10% ammonia 50 II 10% solution of sodium chloride Remove the sheet from the apparatus and dry it in a current of warm air from a hair-dryer. Spray indicator I on to the dry sheet. Dry, then spray the sheet with the sodium chloride solution, leave to dry and expose the sheet to daylight in front of a window. The spots appear dark violet on a mauve ground. Above 50 gamma the center of the spot is yellowish. Results. The indices Rf obtained for thioglycolic and thiolactic acid are the following: Thioglycolic acid 0.28 0.02 Thiolactic acid 0.42 0.02 Sensitivity. Five-gamma thioglycolic or thiolactic acid still give a visible spot. NOTICE Members of the Society may borrow books from the library of the Society at The New York Academy of Sciences, 2 East 63rd Street, New York 21, N.Y.

PLASTIC COATED PUSH BUTTON CONTAINERS* By A. R. M^RKs and E. BUOZ•LEK lt/heaton Plastics• Company, Mays Landing, N. ]. WE PUSH A BUTTON to ring the door bell, to summon an elevator or call our secretary. These are signal buttons. We push a button to light a lamp, ventilate a room or get a quick sun tan. These are appliance buttons. We push a button to kill flies or other insects, to decorate a Christmas tree, to lacquer and set our hair, to apply a fragrance advertised as "Bait to capture your true love"--and if they only knew how badly we wanted to be captured: these are aerosols. "Aerosol" is a term applied to products that are pressure-propelled. Fundamentally, pressurized products are packaged with liquefied gases, such as Du Pont's Freons, General Chemical's Genetrons and Penn Salt Chemical's Isotrons. These are the same agents used as coolants in re- frigeration and air conditioning units. The pressure-propelled type of package made its first appearance early in World War II as a container and dispenser of insecticides. Postwar developments put the aerosol container into civilian use as a better dispenser for a wide variety of liquids and semi- solids. But, there was one major drawback, the fact that many chemicals and food products are highly corrosive in contact with metals. Or, metal has a detrimental effect on the chemicals or products contained therein. This was the problem that presented itself to the Wheaton Company in 1951. Some number of failures, many thousand dollars and 6000 miles later a new aerosol container was filling the atmosphere with air deodorant, liquid fertilizers, sun tan oils and spot removers, blow torch fuel and cold relief remedies. The new aerosol container is a plastic coated glass bottle. It will withstand internal pressures far in excess of the normal 15 to 25 lb. loading pressure. It further offers the flexibility of design and decoration found only in glass or plastic cosmetic containers. The coating of glass bottles has two fields of application--the non-pres- surized and pressurized. In the non-pressurized field we refer to this as an industrial coating. It is used to make a package break resistant, add color, warmth of feel, prevent fragmentation and, with an added opacifier, a * Presented at the May 10, 1957, Meeting, New York City. 386