Sept. 16, 1886 ] 
NATURE 
485 
burgh, and more fully in a paper which will appear in the next 
number of the Quarterly Fournal of Mizros:opical Science. At the 
beginning of the present year the systematic examination of the 
ova of all species of fish which could be obtained was com- 
menced. The pelagic ova of the cod, haddock, whiting, and 
gurnard had been examined in the previous spring, and those of 
a large number of additional species have now been figured and 
described at successive stages of development. The results of 
this work are now being published in full by the Royal Society 
of Edinburgh, and will appear as a memoir in the Society’s 
Transactions. (2) The faunological investigations have been 
carried on as time permitted since the opening of the Station, 
and have, since June last, been receiving particular attention. 
A Report on the Chzelopoda, in the preparation of which Mr, 
G. A. Ramage is giving his assistance, will appear in the 
coming autumn ; a Report on the Sponges is being prepared by 
Mr. J. Arthur Thomson; and miscellaneous notes on other 
classes will be incorporated with these special Reports. (3) 
The following is a list of those who have carried on studies at 
the Station :— 
Nane | Began | Left Subjects 
1885. Dr. Kelso, Edinburgh C6 | Aug. Sept. 26 Teleostean ova 
And. D. Sloan, Edinburgh | Aug. 8 April 1886 | Ccelenterates 
A. H.W. Macd_nald, E-in- | 
oieite teas coo or. eee ee || MOL Noy. 1885 | General 
G. L, Gulland, Edinburgh | Oct. 6 Nov. 1885 | Crustacea 
1886. G. A. Ramage, Edinburgh | Ju e3 — Chzelopoda, &c. 
M, M. Kay, Edinburgh ... | July 24 | — General 
Miss Macomish, London... | Aug. 2 | | Mollusca 
J. Arthur Thomson, Edin- | | 
[Sie Go cs cos oop | pee) _— Sponges, &c. 
The yacht is kept up in the same condition as at the opening of 
the Station, and the number of men is unaltered. The ark at 
Millport is again in use this summer, and is in the charge of Mr. 
David Robertson. Mr. Cunningham worked there for one 
week in June, having found at Millport a particularly favourable 
opportunity for the study of Teleostean ova. Many other 
naturalists have taken part in the AZedusx’s dredgings in the 
Clyde district during the present summer. The services of Alex. 
Turbyne, the keeper of the Station, in making excursions in 
trawlers to procure fish ova, have been most valuable. All 
those interested in the Station are greatly indebted to Mr. 
Robert Irvine, of Royston, for the friendly assistance which he 
has always been ready to afford on every occasion. Preserved 
specimens of marine animals and plants are still sent out to 
applicants, and some attention is being paid to the question of 
oyster-cultivation in the Firth of Forth. 
J. T. CunnincHaM, B.A., F.R.S.E. 
Physical marine research has, from the commencement, formed 
one of the distinctive features of the Scottish Marine Station. 
During last year work has been carried onin this direction by Dr. 
H. R. Mill and Mr. J. T. Morrison ; other gentlemen have occa- 
sionally made use of the facilities of the Station. Regular 
meteorological observations are continued twice daily, and in- 
clude the temperature at surface and bottom of the water. An 
elaborate set of experiments with Mr. John Aitken’s new forms 
of thermometer-screen were completed last year by Mr. H. N. 
Dickson, who has discussed the results in connection with 
those obtained by him with the same apparatus on Ben 
Nevis. Experiments with various anemometers are still in 
progress. Atmospheric dust is being collected on several 
islands in the Firth of Forth, by means of large funnels 
and carboys, which are periodically emptied and the con- 
tents forwarded to Mr. Murray for examination. Monthly 
trips along the Firth of Forth for the observation of tem- 
perature and salinity have taken place regularly from river 
to. sea; preliminary results have been communicated to the 
Royal Society of Edinburgh from time to time, and a complete 
discussion of salinity is nearly ready for publication. It shows 
remarkable relationships between salinity and configuration, 
which have suggested new definitions of the words *7ver, estuary, 
and firth. Special attention has been devoted to the relation of 
salinity and temperature to tide in the estuary of the Forth. 
Besides the observations of the scientific staff of the Station, 
thermometer readings are taken by volunteer observers at dif- 
ferent parts of the Forth river-system and in the adjacent parts 
of the North Sea. The A/edusa has made regular trips on the 
Clyde since April last at intervals of two months. Temperature 
and salinity observations are made in all parts of the estuary and 
firth from Dumbarton to the North Channel, and in all the 
connected lochs. These trips have yielded results of great 
interest and novelty. They are communicated in several papers 
to various Sections of the present meeting. The temperature of 
two deep fresh-water lakes—Loch Lomond and Loch Katrine— 
has been observed at all depths once a month since November 
1885, in continuation of Mr. J. Y. Buchanan’s work. Daily 
temperature observations have been established on a number of 
rivers and at several points on some. The Station has charge 
of observations on the Thurso, in the north of Scotland, the 
Forth and Teith, and the Tweed; and it has also been the 
means of inducing independent observers to undertake similar 
work on the Tummel (a tributary of the Tay), the Tay, and 
the Derwent, in Cumberland. These are all salmon rivers, 
and the observers being interested in fishing have already 
succeeded in showing some connection between temperature 
and the movements of salmon. In consequence of experi- 
ence gained in physical marine investigations the apparatus 
used for the purpose has been progressively modified and 
improved—the Scottish thermometer-frame and water-bottle 
may be pointed to as special instances. The Station has, since 
September 1885, been able to advise and assist several public 
bodies in starting observations of temperature and salinity, the 
National Fish Culture Association of England, the Dundee 
Harbour Trust, and the Fishery Board for Scotland being 
amongst the number. Thermometers have been lent to several 
naturalists for use on short scientific voyages. The collection of 
all existing records of sea and river temperature round the coast 
of Scotland is proceeding, and promises, when completed, to be 
of great value in showing the different sea-climates of the east 
and west coasts—a question of much importance in relation to 
the distribution of marine species. 
HuGH RoBeErT MILL, D.Sc., F.R.S.E. 
Report upon the Depth of Permanently Frozen Soil in the Polar 
Regions, its Geographical Limits and Relations to the Present 
Poles of Gr.atest Cold, by a Committee consisting of Lieut.-General 
be Walker, (C2Biy Eile Ses GEL L StIie fouelha LEILOP, 
(Reporter), Prof. Sir W. Thomson, Mr. Alex. Buchan, Mr. 
F. Y. Buchanan, Mr. Fohn Murray, Dr. F. Rae, Mr. H. W. 
Bates (Secretary), Capt. W. F. Dawson, R.A., Dr. A. Selwyn, 
and Prof. C. Carpmael.—The inquiry referred to the Committee 
necessitated reference to residents in many distant regions, and 
time must elapse befure any large harvest of observations can 
be hoped for ; nevertheless, the Committee are in a position to 
quote several valuable communications, especially one from 
Mr. Andrew Flett, adding materially to what was previously 
known on the subject of the extension of permanently frozen 
soil, or ground ice, in America. It will be convenient to arrange 
the data now available, in their order of latitude. 
1. Lat. 71° 18’ N., long. 156° 24’ W.—At the wintering 
station of the United States Expedition of 1881-82, under Lieut. 
P. H. Ray, United States America, that officer found the 
temperature of the soil 12° F, at 28 feet from the surface, and 
the same at 38 feet. 
2. Lat. 68° N., long. 135° W.—At Fort Macpherson, on 
Peel River, Mr. Andrew Flett, who passed twelve years there, 
reports :—‘‘ The greatest depth of thawed-out earth I came 
across round that post was 34 feet, October 10, 1865. The 
greatest depth of frozen ground was 52 feet 3 inches, Sep- 
tember 27, 1867, near the mouth of Peel River. The bank had 
fallen in ; at the bottom the perpendicular cliff, which I tried 
with a boat pole, was frozen as hard as a rock. A black sandy 
soil. The surface was not above two feet thawed-out. The 
cliff was measured with the tracking line.” This account leaves 
it doubtful whether the frost may not have entered the soil from 
the face of the cliff. On the other hand it is evident that it 
extended to a greater depth from the surface than was measured. 
3. Lat. 67°N., long. 142° W., on the Youcon.—The same 
gentleman writes:—‘‘I spent twelve years on the Pelly or 
Youcon River, on the west side of the Rocky Mountains. Round 
old Fort Youcon ground ice is found at 6 feet ; this I have seen 
in the river banks in September where they had caved in ; but 
no particular notice has been taken as far as I know by any one, 
unless it be Chief Factor Kobert Campbell, now residing in: 
Merchiston, Strathclair, P.O., Manitoba.” 
4. Lat. 65° N., long. 120° W., on the Mackenzie River, about 
ten miles above the mouth of Bear River.—The same gentleman 
writes: —‘‘ I have seen many landslips on the Mackenzie, which 
