268 CURRENT ToPIcs . [J. F. I.

a car has received its quota, additional calls will b~ registered on a following car. In this way, the service is divided between all the floors, and an equal service is given to all floors au tomat ica l ly wi thout the necessity of " s p o t t i n g " cars. The condition is elimi- nated whereby the upper floors get exceptionally good service and the lower floors poor service. Because of varying traffic conditions, it m a y be necessary to adjust the quota. This is done by means of a switch at the s tar ter s tat ion on the ground floor. Quota control decreases loading t ime by ins tant ly i l luminating the lantern a t the par t icular ear entrance to the floor so tha t passengers will be a t t r ac ted and be ready to step in the car when it stops.

R. H. O.

Pe r i l l a . - -Th i s is an oil t ha t has been unapprecia ted for genera- tions and due to modern chemis t ry has suddenly become of much interest. According to the fndustrial Bulletin of Ar thur D. Little, Inc. for December 1936 the United States will impor t from Japan at least I5O,OOO,OOO pounds of it this year as against half tha t much the year before, and a negligible amount before that . The perilla plant is now star ted as an American crop. The oil has been found of great value in making soya-bean oil useful for paints, varnishes and linoleum in enabling it to dry sufficiently fast. Perilla oil is pro- duced from t iny seeds of a plant of the mint family closely related to the highly colored coleus of our gardens. The plant is an annual which needs a long growing season and does best in the southern states. The Manchur ian crop, most of which goes to the United States, is being rapidly increased, and this together with our own raising is expected to make the oil well known fairly soon. The Japanese are as much interested in the press cake as in the oil, and use it as a fertilizer for their mulber ry trees. The cake m a y soon find other than fertilizer uses in this country. Perilla oil alone is not of much interest as a paint oil, for it yellows ra ther badly in the light (whereas linseed oil yellows in the dark). Further , it has to be boiled or ket t le- t reated if it is to be used as a paint oil. I t is in blends, par t icular ly with soya-bean oil, t ha t perilla achieves the balance of propert ies tha t makes it the near sensation it has become. Paints and waterproofings of good drying propert ies and great durabi l i ty are possible with this combinat ion of oils from Manchukuo.

R. H. O.