Abstracts of Recent Technical Papers from Bell System Sources (01 July 1926)

Physical Review, Vol. 27, pp. 318-328, March, 1926. of America 524 and Review of Scientific Instruments, Journal of the Optical Society March, 1926, pp. 173-194. ABSTRACTS OF RECENT TECHNICAL PAPERS 525 may be mentioned the fact that the original picture, for instance a photographic negative, is not seen by the operator at the receiving end. He cannot, therefore, by using his photographic knowledge and experience, choose printing media and decide upon conditions of exposure and development. 

As an illustration of the opportunities introduced by an electrical picture transmission apparatus may be noted the possibility of so poling the electrical elements that the received picture may be either a positive or negative, irrespective of the nature of the original at the sending end. While in other picture transmission systems other problems arise peculiar to these systems, it is believed that although the questions considered are those presented in commercial operation in the Bell System, they are, to a certain extent, common to all electrical picture transmission apparatus. 

A Radio Field-Strength Measuring System for Frequencies up to Forty Megacycles.3 H. T. FRIIS and E. BRUCE. In previous types of radio field strength measurement apparatus it is very difficult to reproduce accurately the small comparison voltages at very high frequencies, due to reactive effects in the attenuating networks.