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Stability of vitamin C in dried orange juice
468
MALCOLM MACLAREN.
IJ. 1:. 1.
system or entirely by voltage control through the use of a motor generator set. In the last case the duty may be more severe upon the generator of the motor generator set than upon the variable speed motors, for heavy currents have to be commutated at low voltages and consequently very weak fields. We: are inclined to think of the direct-current motor with its commutator as being particularly vulnerable compared with the rugged squirrel-cage type of induction motor, and yet we find the direct-current motor selected for the most exacting requirements in the operation of steel mills where the conditions of service are probably more severe than in any other line of work. There they are employed not only for the heavy duty of cranes, hoists, transfer tables and for handling the molten metal where it is 'absolutely essential to guard against loss of motive po,wer, but also for driving the main rolling mills. Alternating-current motors may be used where the drive is in one direction, but when the motor is reversed with every passage of the metal through the rolls, the interpole compensated field type is employed. High speed of reversal is essential and in some of the recent installations the motors are brought from full speed forward to reverse in three seconds. The motors for this service range in capacity from about 3o0o to 8ooo horsepower at maximum speeds from 5° to I2o r.p.m, and represent the largest direct-current motors so far constructed. With the tremendous development that has taken place in alternating-current practice within recent years, there is a tendency to think of direct-current apparatus as being somewhat out of date. I trust that this review of the subject may serve to remind us that in many extensive lines of work the direct-current interpole motor still reigns supreme. Stability of Vitamin C in Dried Orange Juice.~GERTRUDE J. HUMPIaREY (Jour. Biol. Chem., I926, 69, 5II-512) has tested biologically, a. preparation which had been made by addition of sugar to orange jmce to produce 25 per cent. of total solids, followed by drying and storage in a partial vacuum. The preparation had been kept for over five years. Young guinea-pigs were fed a diet which produces scurvy, and received daily doses of the dried orange juice for a period of thirty-two days. They failed to develop scurvy. Therefore, the anti-scorbutic vitamin, or water-soluble C, in the dried orange juice had retained its activity at the end of five years' storage. J. S. H.
MALCOLM MACLAREN.
IJ. 1:. 1.
system or entirely by voltage control through the use of a motor generator set. In the last case the duty may be more severe upon the generator of the motor generator set than upon the variable speed motors, for heavy currents have to be commutated at low voltages and consequently very weak fields. We: are inclined to think of the direct-current motor with its commutator as being particularly vulnerable compared with the rugged squirrel-cage type of induction motor, and yet we find the direct-current motor selected for the most exacting requirements in the operation of steel mills where the conditions of service are probably more severe than in any other line of work. There they are employed not only for the heavy duty of cranes, hoists, transfer tables and for handling the molten metal where it is 'absolutely essential to guard against loss of motive po,wer, but also for driving the main rolling mills. Alternating-current motors may be used where the drive is in one direction, but when the motor is reversed with every passage of the metal through the rolls, the interpole compensated field type is employed. High speed of reversal is essential and in some of the recent installations the motors are brought from full speed forward to reverse in three seconds. The motors for this service range in capacity from about 3o0o to 8ooo horsepower at maximum speeds from 5° to I2o r.p.m, and represent the largest direct-current motors so far constructed. With the tremendous development that has taken place in alternating-current practice within recent years, there is a tendency to think of direct-current apparatus as being somewhat out of date. I trust that this review of the subject may serve to remind us that in many extensive lines of work the direct-current interpole motor still reigns supreme. Stability of Vitamin C in Dried Orange Juice.~GERTRUDE J. HUMPIaREY (Jour. Biol. Chem., I926, 69, 5II-512) has tested biologically, a. preparation which had been made by addition of sugar to orange jmce to produce 25 per cent. of total solids, followed by drying and storage in a partial vacuum. The preparation had been kept for over five years. Young guinea-pigs were fed a diet which produces scurvy, and received daily doses of the dried orange juice for a period of thirty-two days. They failed to develop scurvy. Therefore, the anti-scorbutic vitamin, or water-soluble C, in the dried orange juice had retained its activity at the end of five years' storage. J. S. H.