In addition to the above, the Signal Corps, acting upon the invitation of the several Entente Governments, dispatched some 1,200 cadets to England, France, and Italy last year, who were to receive primary and advanced training in aviation schools of those countries. The experience of a great many of these men has been most unfortunate in that at some of the schools a very serious delay has occurred in providing them with the training planes, which it was expected would be manufactured in foreign factories in sufficient numbers. As a result, several hundred of the American cadets have been practically idle and have made no progress. About 450 of them are reported as having completed the primary training, after long delay. The Signal Corps is giving serious consideration to the advisability of bringing the remainder back to the United States to be trained. With the exception of this severe disappointment, the primary training of our aviators, according to the testimony of the aviation officials, appears to be progressing favorably. For some time after the inception of the work the output of primary training planes in this country for use in our schools gave ground for grave concern. In recent weeks, however, the output has been greatly increased, and there seems to be no doubt of the Signal Corps having an amply sufficient number in the future. On April 1, 1918, 3,458 primary training planes had been completed. The advanced training planes are being turned out in accordance with the schedule and estimates laid down at the inception of their manufacture. In advanced training planes four types are being made, the total number up to date manufactured being 342. In these planes three types of engines will be used, of which 965 have been completed. The Liberty motor is not suitable for use in these planes. It is apparent from the evidence that the twelve-cylinder Liberty motor is just emerging from the development or experimental stage. Since the original design and the setting up of the first completed motor in July, 1917, a large number of changes have been found necessary, many of them causing delay in reaching quantity production. Within the last two months changes of considerable importance have been made which, it is hoped, will make the motor serviceable for combat planes of the defensive type and for bombing and observation planes. Twenty-two thousand five hundred Liberty motors have been ordered, 122 have been completed for the army, and 142 for the navy. Four have been shipped overseas. Some of those already delivered are being altered to overcome the defects ascertained during the last few weeks. It is understood, however, that these alterations will consume but a very short time.