A NEW KIND OF TELEPHONE RECEIVER AND TRANS- 
MITTER 
C. W. HEWLETT 
The Tone Generator described in these proceedings a year ago 
has been used successfully as a telephone transmitter and receiver. 
A loud speaker about eight inches in diameter has been made 
which will speak loudly enough to address a small gathering of 
people, say a hundred. The main advantage of the instrument is 
its faithfulness of reproduction of speech and music, the failure 
to do which is the chief disadvantage of all other known telephone 
instruments. The instrument when used as a transmitter is free 
from all the usual transmitter noises, and from distortion due to 
resonance of the diaphragm. By means of a three stage amplifier 
the voice currents from the transmitter have been amplified 15,000 
times without the introduction of noises. With this arrangement 
the transmitter has been able to reproduce in a telephone receiver, 
ordinary conversational speech spoken at a distance of 50 feet 
from the transmitter. The chief phase of the problem which is 
being studied at present is to introduce into the loud speaker a 
fairly large amount of electrical power in the form of undistorted 
voice currents. 
One marked improvement which has recently been made in the 
use of the instrument is to use the direct plate current of the 
accessory vacuum tubes to serve as the polarizing direct current 
for the telephone instrument. 
State University oe Iowa. 
THE SCATTERING OF HOMOGENEOUS X-RAYS OF 
WAVE LENGTH 0.712 A° UNIT BY CARBON, 
LITHIUM, AND HYDROGEN 
C. W. HEWLETT 
The angular distribution of the scattering of the Ka radiation 
from a molybdenum X-ray tube by powdered graphite, diamond 
splints, benzene, mesitylene, and metallic lithium has been deter- 
mined with an X-ray spectrometer by the ionization method. The 
solid substances give maxima of scattering in the places found by 
