542 NATURE. [JuLy 25, 1912 
room, a centre of education. In a paper on the | so-called “‘ sixth sense”. as it exists in bats, which, 
influence of museums on the reform: of classical | even when blinded, are able to find their way through 
studies, the Rev. Prof. H. Browne followed up these 
ideas by insisting that the facts and:conclusions of 
archeology, as they. may be illustrated by a well- 
chosen collection, remove from classical studies the 
sense of unreality; and by complaining that Con- 
tinental museums’ do more than British institutions 
for classical teaching. Mr. James Ward (headmaster 
of the Dublin Metropolitan School of Art), in a paper 
on the relation of schools of art to museums, made a 
somewhat similar complaint in deploring the scanty 
representation of good examples of modern applied art 
in our national institutions as compared with those 
of many Continental cities. Inthe discussion on 
this paper, Mr. H. Bolton (of the Bristol Museum) 
laid stress on the help given to students of decorative 
design by the loan of specimens of birds, insects, and 
shells from the zoological collection under his care. 
The presence of Dr. F. A. Lucas (director of the 
American Museum of Natural History, New York) 
was exceedingly welcome at the meeting, and he con- 
tributed a valuable paper on the school work of some 
American museums. At Brooklyn and New York, 
loan collections made up for schools led to lectures 
to children in the public museum galleries, and the 
establishment of these was followed by exhibits in 
the galleries arranged so as to appeal especially to 
school children. In the discussion on one of the 
papers, Dr. N. Annandale (director of the Indian 
Museum, Calcutta) directed attention to the possible 
danger of popularising exhibits, labels, and guides to 
such an extent as to discourage thought on the part 
of the casual visitor, and actually to repel the earnest 
student. Dr. Lucas, in reply to this, expressed the 
opinion that the student can take care of himself, and 
that it is impossible to make things too easy for the 
general public in museums. 
There were several technical papers on both art 
and natural history subjects. The educational aspect 
of the curator’s work was, however, the predominant 
feature of a distinctly profitable and well-attended 
meeting. In 1913 the association proposes to gather 
at Hull, under the presidency of Mr. E. Howarth (of 
the Public Museum, Sheffield). 
A NEW SYSTEM FOR PREVENTING 
COLLISIONS AT SEA.1 
IR HIRAM MAXIM long ago established a high 
reputation as a mechanical engineer, and is the 
author of many ingenious inventions, amongst which 
machine guns and flying machines are probably the 
best known. The loss of the Titanic led him to 
ask : ‘‘ Has science reached the end of its tether? Is 
there no possible means of avoiding such a deplorable 
loss of life and property?” ‘At the end of four 
hours,”” he adds, “it occurred to me that ships could 
be provided with what might be appropriately called 
“a sixth sense’ that would detect large objects in 
their immediate vicinity without the aid of a search- 
light.” Having worked out the invention in con- 
siderable detail, and satisfied himself of its value by 
means of experiment, Sir. Hiram Maxim has secured 
patents for the apparatus in the leading countries of 
the world, and now publishes a full description of the 
system and a justification of his belief in its practical 
success if adopted. 
The mode of treatment followed in the pamphlet is 
popular, and is obviously intended to meet the case 
of readers unfamiliar with acoustics. | Considerable 
space is devoted to descriptions and illustrations of a 
By Sir Hiram S. 
(London: Cassell and Co., Ltd., rgr2.) 
NO. 2230, VOL. 89] 
1A New System for Preventing Collisions at Sea” 
Maxim. Pp. xv+147. 
tortuous passages, to avoid unseen obstacles, and to 
capture their food. That -section of the work will 
receive no attention in this brief notice. Nor need 
anything be said respecting lengthy references made 
by Sir Hiram Maxim to Tyndall’s well-known experi- 
ments on the transmission of sound through air 
under various conditions of the atmesphere, including 
fog. The facts and conclusions therefrom to which 
reference is made are well known to men of science 
and to all persons concerned with aids to navigation; 
the real interest of the present publication lies in its 
suggestion of a means by which the author hopes to 
lessen the risk of collision occurring between ships, 
or between ships and icebergs, derelicts, and other 
obstructions to navigation, when they cannot be seen 
at any reasonable distance. 
The suggested apparatus embodies a modified form 
of “siren,” through which high-pressure steam can 
be made to flow in order to produce sound-waves 
having about fourteen to fifteen vibrations per second, 
and consequently not coming within the range of the 
human ear. These waves, it is asserted, would be 
capable of travelling great distances, and if they 
struck against a body ahead of the ship they would 
be reflected towards their source, ‘‘ echo waves ”’ being 
formed. The second part of the apparatus, or “‘re- 
ceiver”’ for*these echo waves, consists of a large 
diaphragm tightly drawn over a  drum-shaped 
cylinder. Atmospheric pressure is always to act 
equally on both sides of the diaphragm, which can 
“vibrate freely in response to the waves of the echo, 
and its vibrations are made to open and close certain 
electrical circuits, which ring a series of bells.” 
Audible notice is thus to be given of any obstruction 
situated above the water surface and ahead of the 
ship. A third device provides a means of obtaining 
diagrammatic records of the disturbances in the air 
ahead of the ship, and its intended operation is thus 
described :—‘t When there is no noise, except that due 
to the action of the sea waves, a wavy line is pro- 
duced; but whenever the vibrations sent out by the 
vibrator strike an object and return, the wavy line 
on the paper becomes very much increased in ampli- 
tude.” Sir Hiram Maxim conceives that it may be- 
come possible to send out a series of pulsations that 
will travel over a distance of 100 miles and be receiv- 
able by his ‘“‘recorders,’”’ and he anticipates being able 
to approximately determine from these records both 
the distance and the size of any object which may 
reflect the waves. It is umnecessary to dwell upon 
the details of his methods of approximation; they can 
be studied in the pamphlet by any person interested 
therein. 
The main question which arises in considering these 
proposals is whether, if all that Sir Hiram Maxim 
anticipates were accomplished, the object at which 
he aims would be attained, and greater security 
against collisions achieved, especially in passenger 
steamships of high speed. Sir Hiram Maxim admits 
frankly that, except in dark, foggy, or stormy 
weather, there would be no use for the apparatus 
unless it was used for communicating with other 
ships. Wireless telegraphy is obviously far superior 
for the last-mentioned purpose, and there is a good 
prospect of its installation being made compulsory 
for passenger steamers. In the circumstances de- 
scribed, the best chance of avoiding accident is 
| obviously to be found in reduction of speed and close 
observation. Similarly, when making the land in 
fog or thick weather, everything must depend upon 
the caution and skill of commanders; and while it is 
true (as Sir Hiram. Maxim. says) that a strong echo 
