asserted that misdirected aviation development is largely responsible for the present condition of aeronautics in the United States. On the basis of the experience of the past few years, it appeared that the supposed advantages of multi-engined and all-metal planes have been important causes of false leads in the development of commercial service. Mr. Loening claimed that the useful loads per horsepower are ahnost as great in a single-engined plane as in one equipped with two or more engines. He declared that it is a mistake to assume that a duplication of engines gives greater safety from engine failure, since nlost of the causes of failure, such as weather conditions, sleet and ice, would stop all the motors. He also said that it is very rare that the engine fails in itself. Something usually fails in the gas line or the water line. Engines applicable to war-planes are not suitable for commercial planes. The following were given as desirable features in the development of the power-plant in commercial planes. (I) Muffling devices. (2) Geared-down engines, or, better still, slower running engines to improve the propeller power, particularly in starting and climhing speeds. (3) Further development of the reversible pitch propeller.
Before the same society Professor E. P. Warner presented a paper which included some statistics of the passenger service 1)etween England and the continent. In the first eleven months of the service there was a total of twenty-four accidents, in four of which one or more persons were killed. The pilot was killed in each case, but only one passenger in the entire period. The average death-rate for pilots was one for every 241o hours in the air. The passenger rate is one death for every 67,oo0 carried, and taking into consideration the fact that the average speed is 9 ยฐ m.p.h., one fatality for every 1,64o,ooo passenger miles.
H.L.
Prickly Pear Oil.rain the manufacture of an edible jelly, known as qucso, from the fruit of the prickly pear, the seeds are discarded as waste. These seeds are rich in oil; the seeds of a variety of white prickly pear, known as tuna blaca de huerta, contained IO.89 per cent. of oil. By extraction of the seeds with petroleum ether, the oil was obtained as a greenish-yellow, odorless, somewhat viscous oil. Among its constants were: Acid value, 3.o9; saponification number, 189.5; iodine nmnber, 116.3; Reichert Meissl number, 2.8; Hehner n.umber, 93.81. From the results of his study. S. LOMANITZ (Journal Ind. and Eng. Chem., 192o, xii, 1175 ) coneludes that this oil should probably he placed among the semi-drying oils, and might be used in the arts if prodnced in sufficient quantity.
J. s. H.