May 31, 1901.] 
all the circuits tuned to the same period. The 
fact that signalling had been successfully carried 
out over a distance of 50 kilometers with a 
cylinder only 1.25 meters high and one meter in 
diameter led to the possibility of constructing 
portable apparatus for use in the field. He had 
designed a complete installation on a steam 
motor-car, on the roof of which was placed a cy- 
linder, only six or seven meters high, that could 
be lowered while traveling. By means of this, 
communication had easily been carried on with 
a syntonized station 50 kilometers distant, a 
25-cm. spark induction coil, taking about 100 
watts, being used for transmitting. A strip of 
wire netting dragged behind the car was sufii- 
cient forearth connection, or inlieu of any earth 
connection the electrical capacity of the boiler 
might be utilized. As to the distance over 
which signalling had been effected, last spring 
he established a station at the Lizard and 
opened communications with St. Catherine’s— 
a distance of over 300 kilometers. The amount 
of energy used in this case was not more than 
150 watts, and the aerial conductor consisted of 
four parallel vertical wires 14 meters apart and 
48 meters long, or of a strip of wire netting of 
the same length. In conclusion, Mr. Marconi 
gave some examples of the progress made in 
the practical utilization of his system, and also 
briefly examined a method proposed by Pro- 
fessor Slaby. 
WIRELESS TELEGRAPHY IN THE NAVY. 
ADMIRAL BRADFORD, chief of the naval 
bureau of equipment, has given out the follow- 
ing extract from the report of the board which 
has investigated the question of transmitting 
messages by wireless telegraphy : 
‘‘From the examination of the subject, as 
outlined in the orders of the department, the 
board makes the following recommendations: 
‘1. That the use of homing pigeons be dis- 
continued as soon as wireless telegraphy is 
introduced into the navy. 
“9. That, pending such action, no new pi- 
geon codes be established. 
‘3. That wireless telegraphy be adopted by 
the navy for transmission of messages between 
distant points. 
“Referring to the last recommendation, the 
SCIENCE. 
875 
board is of the opinion that a high degree of 
special electrical training is demanded for the 
successful operation of any system of wireless 
telegraphy, and it therefore suggests as neces- 
sary the establishment of two stations suffi- 
ciently far removed from each other for the 
training of officers and men. 
‘Tn its opinion this requirement would be 
best met by the establishment of such stations 
at the Navy Yard, Washington, and the Nayal 
Academy, Annapolis. If wireless telegraphy 
fulfills what now seem to be its possibilities, 
the cadets should be thoroughly trained in it. 
‘« As the investigation made by this board is 
not technical, there being no apparatus of any 
kind ready for test, but general in its character, 
such partial examinations as outlined above 
would not change the recommendations already 
made. 
‘‘The selection of any special system of 
wireless telegraphy is, in the opinion of the 
board, very largely a matter of business detail. 
“‘If for any reason any competitive test of 
different systems is thoroughly desirable the 
board recommends, in view of the fact that the 
improved Marconi apparatus will not be avail- 
able for several months, and that improvement 
in other systems may occur in that interval, 
that it be made only after due notice and prep- 
aration therefor, and by a special board of ex- 
perts appointed for the purpose.’’ 
THE AMERICAN ASSOCIATION FOR THE AD- 
VANCEMENT OF SCIENCE. 
ARRANGEMENTS for the Denver meeting of 
the American Association for the Advancement 
of Science are locally assuming very definite 
shape. A meeting of the Colorado Science 
Teachers Association was held in Denver on 
May 11th and all the members of the American 
Association residing in Colorado were invited 
to attend, a special point being made in the 
call that the meeting would consider the August 
meeting of the American Association. The 
cooperation of the Society was pledged to the 
Local Executive Committee, and the committee. 
itself was organized by the election of Mr. 
George Lyman Cannon as chairman and Mr. 
Arthur Williams, secretary of the Chamber of 
Commerce and Board of Trade, as secretary. 
