Apri 18, 1907 | 
NATURE 
597, 
to do so unless Italian archeologists support their words 
by actual deeds?. One simple fact outweighs all their 
written and spoken utterances. Nowhere in Italy is any 
foreign enterprise at work, and never has any foreigner 
been invited to give his time and his talents to what is, 
in their own admission, a common cause. If Italian 
archeologists would pay to other nations the graceful 
compliment of employing, now and then, their students as 
assistants; if those derelict excavations on the shore of 
the Gulf of Taranto—whose need is so pressing and 
whose secrets are so necessary to history—could be, even 
temporarily, confided to foreign institutions; then, and 
not till then, their assurances would carry weight.’” 
PROGRESSIVE WAVES IN RIVERS. 
HE stationary waves produced by the interaction of a 
rapid stream with its bed have been the subject of 
several investigations. ‘he author finds that by a special 
mode of vision described in the paper the simultaneous 
presence of waves progressing down-stream can be readily 
detected. 
In a very shallow stream with a steep channel, the pro- 
gressive wave becomes the principal and obvious, instead 
ot a subordinaie and obscure, feature. In this case the 
velocity of flow is much reduced by friction. The slightest 
excess of retardation at any point momentarily increases 
the depth there, and increase in depth (where the depths 
are small) increases the velocity, at any rate in the upper 
layer. Continuous motion is therefore impossible, and is 
replaced by a gushing flow. If the bed be of nearly 
uniform cross-section, the gushes take the form of regular 
transverse progressive waves. If, on the other hand, the 
cross-section of the channel be very uneven, there may 
be no lateral coordination, and the intermittence of flow 
is only detected by the rushing sound and the beating 
action of the water against an immersed body. 
Measurements showed that the total velocity of these 
roll-waves was equal to the velocity of the current plus 
the velocity of a long wave in water of the observed 
depth. 
All waterfalls tend to break up into conical masses called 
water-rockets, and in rare cases a fall may be seen which 
consists of a slow procession of well-separated ‘‘ rockets "’ 
ranged in roughly horizontal lines. A case is described in 
which this beautiful appearance was due to the formation 
of roll-waves above the fall. 
Roll-waves spontaneously arising in very shallow con- 
duits occur in groups, and the growth of amplitude and 
wave-length was measured in the case of the conduit of 
the Griinnbach at Merligen, on the Lake of Thun. 
Roll-waves in shallow mountain rivers due to heavy 
rains in the gathering-ground of the tributary streams are 
solitary, and, coming without warning before the turbid 
waters arrive, are dangerous to anglers, who are familiar 
with the phenomenon on the Tees, Ure, Swale, and other 
rivers. The uniform cross-section of the Tees near 
Barnard Castle, and of the Ure near Aysgarth, is peculiarly 
favourable to their formation and growth. 
The cross-stream progressive waves observed by the 
author in the Whirlpool Rapids of Niagara are a secondary 
phenomenon arising from the varying amplitude of the 
familiar stationary waves, a variation which the author 
traces to its cause. When their interference occurs at the 
intersecting crest of two stationary waves there ensues 
one of those great leaps of water which present so splendid 
an appearance in these rapids. The author invites special 
attention to the points in which his explanation of these 
phenomena in Niagara Rapids differs from those hitherto 
current. 
Tidal bores are the only form of progressive wave in 
rivers which had hitherto received much scientific atten- 
The author deals with the question of what deter- 
mines the place of origin of the tidal bore in the River 
, vevern, and what is the cause of its apparently capricious 
variation in magnitude. Briefly, the bore originates where 
the slope of the channel is steep, but in the upper, not 
the lower, part of the steep slope, because there is in the 
1 Abstract. of a paper by Dr. Vaughan Cornish in the Geographical 
Journal for January. 
NO. 1955, VOL. 75 | 
upper part no alternative channel among the: sand-banks 
for the last-of-ebb and first-of-flood respectively to pursue, 
but’ at the end of a set of spring tides the flood has so 
far cut in the sand an alternative, straight channel that 
the height of the bore is reduced. An excess of land- 
water, on the contrary, so strengthens the ebb that it 
tends to make a deep, solitary, curved channel up which 
the flood must force its way, increasing the height of the 
bore. 
UNIVERSITY AND EDUCATIONAL 
INTELLIGENCE. 
Tue Western University of Pennsylvania has conferred 
the honorary degree of LL.D. upon Sir Robert Ball, Sir 
Robert Cranston, Sir William Turner, Sir William Preece, 
Mr. Marconi, Dr. Chalmers Mitchell, Dr. John Rhys, the 
Rev. E. S. Roberts (Master of Caius College, Cambridge), 
and Mr. Edwin Abbey. 
A CONFERENCE on the teaching of hygiene and temper- 
ance in the universities and schools of the British Empire 
will be held at the Examination Hall, Victoria Embank- 
ment, on St. George’s Day, April 23. The chairman at 
the morning session will be Lord Strathcona, and at the 
afternoon session Sir John Gorst. 
Tue annual exhibition of students’ work will be held at 
the Borough Polytechnic Institute on Saturday, April 20, 
from 6-9.30 p.m. ‘The workshops, laboratories, drawing 
offices, girls’ trade school, domestic economy rooms, and 
other departments of the institute will be open for inspec- 
tion, and practical work will be carried on during the 
evening. 
Tue Times correspondent at Ottawa reports that the 
medical building of McGill University, Montreal, was 
destroyed by fire on April 16. The museum, with its 
priceless specimens, is ruined, but a portion of the valu- 
able medical library was saved. The loss is placed at 
100,0001., of which 70,0001. is covered by insurance. The 
crigin of the fire is unknown, but incendiarism is suspected. 
Tue accommodation provided at University of London, 
University College, for the schools of engineering and of 
architecture will be considerably extended before the 
beginning of the next session in October by the additional 
space which becomes available through the removal of 
University College School to Hampstead. The Andrews 
scholarships are offered for competition in May; one of 
these scholarships, value 3o0l., in science andemathematics, 
is tenable in the school of engineering. 
A party of students of zoology from the Birkbeck 
College spent part of their Easter vacation in Jersey shore- 
collecting during the prevailing low tides. More than one 
hundred and fifty species of shore-life were obtained, illus- 
trating nearly all the animal phyla. The success of the 
visit was in great part due to the advice and guidance 
of Mr. J. Sinel, formerly director of the Jersey Marine 
Biological Station. A selection from the species collected 
formed a very interesting exhibit at the annual exhibition 
meeting of the Birkbeck Natural History Society, which 
was held on Saturday evening, April 13. 
Tue reports from the universities and colleges which 
participated, during the year ended March 31, 1906, in 
the: annual grant of 100,000]. made by Parliament for 
“university colleges in Great Britain,’’ and from the three 
colleges in Wales which receive a grant of 4oo0l. each, 
have now been published (Cd. 3409) by the Board of 
Education. Much instructive information can be gathered 
trom the income and expenditure accounts provided by the 
various institutions. With an income of 42,819l., Birming- 
ham University at the end of the year’s working had 
a balance in its favour of 25571. Leeds University, 
though it started the year with 1568/7. in hand, 
after expending 45,7441. ended the year with 395l. 
only to the good. With an expenditure of 53,162/., Liver- 
pool had 532/. in hand at the end of the year. Manchester, 
with an income of 59,155/., came to the close of the year 
with 131]. to the good. Sheffield, which in the year under 
consideration was still a university college, was with an 
income of nearly 25,000. about 1500/. in debt at the end 
