JuNeE 15, 1899] 
MADORL 
163 
no means uniform. There are at times distinct steps, which 
are sometimes visible as such, on the surface of the incoming 
water. At other times the water holds its level for a short 
interval, and then rises rapidly afterwards to make up, as it 
were, for lost time. 
The diagram may also be taken to represent the form of the 
bore, or its profile along the river at any given moment. 
Strictly speaking, this involves the assumption that the whole 
mass of water moves forward at the same speed as the broken 
front which forms the bore itself; which’in all probability is 
not very far from the truth. To assist this view, a scale of 
distances is given on the diagram, which is based upon the 
average rate of advance of the bore in running up the river. 
The bore itself is clearly the broken water at the front edge 
of a long water-slope which advances up the river. The 
greatest rate of rise at spring tides after the bore has passed 
amounts to 3°00 feet in 10m. 5s.; and if we take for the 
average speed 84 miles per hour, the equivalent ,water-slope is 
2°10 feet per mile. This slope appears very moderate in the 
circumstances, although it is really greater than in most rivers, 
except where rapids occur. Also, as a question of hydraulics, 
this slope would undoubtedly prove to be in correspondence 
with the speed of the currents following the bore, if the problem 
were fully worked out. 
It is said that formerly the bore used to be higher than at 
present, owing to changes that have taken place in the bars in 
the river, which now obstruct the channel at low water and 
interfere with its development. No very definite information 
could be obtained as to this. 
On August 22, 1892, a good photograph of the bore was 
obtained, which has been published in a report of the Geological 
Survey. Its height as then measured was 5 feet 4inches. It is 
clear, from the observations, that in three to four minutes after 
the bore passes the water has already risen an extra foot. The 
greatest height which was measured in the above observations 
was 3 feet 3 inches, although it would be a little higher at the 
middle of the river. This may probably be taken as a fair 
average at ordinary spring tides. The maximum no doubt 
occurs when the moon is in perigee at full or change, and also 
at its maximum declination, as this gives the greatest difference 
in favour of one of the two tides in the day. Something also 
depends on the level to which low water falls, as this practically 
adds to the height of the bore. The total difference, however, 
in the level of low water between: spring and neap tides, and 
between one set of spring tides and another, was found to be 
little more than one foot altogether, as observed in the summer 
season. Late in the autumn, when the fresh water outflow of 
the Petitcodiac is increased, the water surface at low tide does 
not fall so low. 
The time of the arrival of the bore, with reference to the time 
of high water, was worked out from the observations obtained 
while the tide gauge was being erected. The time of high 
water at Moncton was obtained by difference of establishment, 
from the tide tables for St. John. The comparison shows that 
the time of arrival of the bore varies from 3h. Im. to 3h. 34m. 
before the time of high water. This result may, however, be 
subject to revision. 
It is hoped that the arrival of the bore, being a well-defined 
moment, may serve to throw light on the whole question of the 
progress of the tide in the Bay of Fundy. 
The only other place in the Bay of Fundy at which the bore 
has been seen is in the upper part of Cobequid Bay. The tide 
there used to arrive as a bore at Maitland, at the mouth of the 
Shubenacadie River; but a change in the position of the sand 
bars below Maitland now prevents this. In running up the 
Shubenacadie, however, the tide still breaks occasionally into 
a ripple or miniature bore. 
THE BOVLE LECTURE ON THE PERCEP- 
TION OF MUSICAL TONE. 
ON Tuesday, June 6, Prof. M*Kendrick delivered in the 
Lecture Room of the New Museums, Oxford, the annual 
Boyle Lecture, the subject being the perception of musical 
tone. The lecture was entirely devoted to a consideration of 
the functions of the cochlea, the minute anatomy of which was 
fully described, The internal ear consists of a complicated 
series of sacs and tubes filled with fluid. In certain situations 
the walls of the sacs contain highly differentiated epithelial 
NO. 1546, VOL. 60] 
structures, which are intimately related to the terminal filaments 
of the auditory nerve. The problem is to explain how the 
pressures transmitted by the foot of the stapes affect these 
terminal structures in such a way as to excite sensations cor- 
responding to the pitch, intensity, and quality of tone. The 
dimensions of the internal ear are so minute as to form only a 
small part of the wave-lengths, even of tones of high pitch, 
The nerve endings are still smaller, but they also act as minute 
portions of any wave, and any reasoning as to the effect of such 
waves is quite irrespective of the small dimensions of the 
receiving organs in the internal ear. If we consider a wave of 
sound as a series of states of condensation and states of rare- 
faction, travelling on continually in one direction ; and, further, if 
we remember that the motion of each individual particle form- 
ing the wave is very small, and is alternately backwards 
and forwards, in the same line as that in which the wave 
travels, we see that the movements, inwards and outwards of the 
base of the stapes, correspond to these oscillations, or, in other 
words, to increase and diminution of pressure with each wave. 
Some of the possible movements of the base of the’stapes were 
described, along with their action on the perilymph surrounding 
the utricle and saccule. We can hear musical tones and noises, 
we have a peculiar auditory sensation to which we give the name 
of beats, and we have the power of analysing a musical tone 
into its component parts. A demonstration was then given of 
the limits of pitch perception, of beats, and of beat tones. As 
regards the perception of intensity, the results of inquiries made 
by Topler and Boltzmann, and more especially by Lord 
Rayleigh, showed the delicacy of the ear for sound, as regards 
energy, is about the same as that of the eye for light. The ear 
may be affected by vibrations of molecules of the air not more 
in amplitude than ‘0004 mm., or O'r of the wave-length of green 
light ; while Lord Rayleigh says ‘‘that the streams of energy 
required to influence the eye and ear are of the same order of 
magnitude.” The question of analysis was next considered, and 
the bearing on it of Ohm’s principle and Fourier’s theorem, as 
regards wave-forms. The lecturer stated that on the whole 
he was not yet satisfied from any observations he had been 
able to make that the ear took cognisance of differences of 
phase, and he pointed out the peculiar difficulties in making 
observations on this point. He was still inclined to support the 
views of Helmholtz. Illustrations were given of wave-forms as 
revealed by the phonograph, and an instrument enabled the 
audience to hear experiments on pitch, intensity, and quality. 
Several violin records of rare beauty were reproduced. The 
lecturer n2xt discussed the probable action of the cochlea. There 
are only three ways in which the ductus cochlearis, which contains 
the nerve-endings, may be affected. Either (1) small vibratile 
bodies may exist between the pressures sent into the organ and 
ihe filaments of the auditory nerve, each vibratile body having 
a frequency period of its own; or (2) individual nerve-fibres 
may be directly excited by waves of a definite period—that is to 
say, there may be differences in the nerve-fibres, so that they 
have a selective action ; or (3) the organ may be affected as a 
whole, all the nerve-fibres being affected by any variations of 
pressures, and thus the power of analysis, which is admitted, 
is relegated from the peripheral to the cerebral organs. The 
first hypothesis seems most probable, for (1) the existence of 
such bodies would give a natural explanation of many, if not 
all, of the phenomena ; (2) the evidence of comparative physi- 
ology points to a gradually increasing complexity in the struc- 
ture of all the terminal organs of special sense, as there arose 
a necessity for differentiation and discrimination in the effects 
of various kinds of stimuli; and (3) investigations into the 
action of all the sense-organs, such as those of touch and tem- 
perature in the skin, of light and colour in the retina, of taste 
in the tongue, and of smell in the olfactory region—all indicate 
specialisation of function in the peripheral apparatus. The 
action of the cochlea was then fully described, and stress was laid 
on the movements of segments of the membrana basilaris causing 
contacts between the apices of the hair-cells and the under-surface 
of the membrana tectaria. Suppose that, in accordance with the 
view of Helmholtz, a segment of the basilar membrane were 
thrown into sympathetic vibration, it would move in a direction 
at right angles to the direction of its fibres. These movements 
would be communicated to the structures lying on its upper sur- 
face, and if we suppose the arches of Corti to be elastic, such 
movements would be transmitted to the hair-cells, These would 
move in the line of their long axis; in other words, their hairs 
would move up and down in the meshes of the membrana 
