Sept. 9, 1886] 
NATURE 
461 
In these aspects the observations for the two years and a half 
from December 1883 to May 1886 have now been discussed. As 
regards decrease of temperature with heizht, it is shown to be 
at the rate of 1° F. for every 270 feet of ascent—a rate which 
closely agrees with the results of the most carefully conducted 
balloon ascents, and of those other pairs of stations over the 
world which are so situated as to yield trustworthy results for 
the inquiry. Ben Nevis Observatory and the Fort William 
station are among the very few such groups of stations that have 
yet been anywhere established. 
4 
q 
i 
* 
In researches into weather phenomena and weather pro- 
gn stics the most important point to determine is the normal 
difference between atmospheric pressure at the top of the Ben 
and at Fort William for the different atmospheric temperatures 
and sea-level pressures. This was empirically calculated from 
the observations, and thereafter the departures from the normals 
were asccrtained for the five observations of each day since the 
Observatory was opened. ‘The results showed a diminution of 
pressure from the calculated normals during the occurrence of 
high winds at the Observatory. The difference not unfrequently 
amounts to the tenth of an inch, and on one day the five con- 
secutive observations showed differences of about a tenth-and-a- 
half inch. ‘This diminution of pressure is doubtless occasioned by 
the winds, as they brush past the Observatory buildings, partially 
sucking out the air from the interior, thus lowering the pressure. 
‘This does not occur till the velocity rises to or exceeds the rate 
of 30 miles an hour. 
It thus became necessary to recalculate the normals for 
pressure, using in the computations only those observations 
which were made when the velocity of the wind fell short of 30 
miles an hour. This recalculation has recently been com- 
pleted, and the inquiry as to the bearing of the Ben Nevis 
bservation, on the weather of the British Islands is being 
pushed forward. 
__ The work at the Ben Nevis Observatory continues to be dis- 
charged by Mr. Omond and his a-sistants in a way that leaves 
nothing to be desired. Since the last meeting of the Society Mr. 
Omond has contributed a-valuable paper to the Royal Society 
of Edinburgh, on the observations of wind force recorded at the 
bservatory. From a comparison of the results obtained from 
the registrations of Prof. Chrystal’s anemometer, and the esti- 
mations of the force of the wind made by the observers on scale 
0 to 12, he has determined the velocity in miles per hour for 
each figure of the scale, 1, 2, 3, &c. The highest figure for 
_ which the double observations were sufficiently numerous, so as 
| to give a good average, was 8, which was found to be equivalent 
to a rate of 73 miles an hour. This velocity is of frequent 
j Occurrence ; and as regards the higher force 11, which occasion- 
‘e 
4 
| ally occurs, Mr. Omond estimates its equivalent at 120 miles an 
hour. Observations on the rain band have been undertaken by 
_ Mr. Rankin, the first assistant. 
__ The hygrometric observations made by Mr. H. N. Dickson at 
the Scottish Marine Station and the Observatory have now been 
partially discu sed by him, and the results submitted to a recent 
meeting of the Royal Society of Edinburgh. These results are of 
| considerable value in determining how far Glaisher’s factors, so 
_ largely used by meteorologists in hygrometric inquiries, may be 
used satisfactorily. As regards the remarkably dry states of the 
atmosphere, which are so prominent a feature in the climate of 
the Ben, Glaisher’s factors are altogether inapplicable, and hence 
the hygrometric observations of the Observatory, therefore, will 
require a specially constructed set of tables. 
The zoological work at the Marine Station has been carried 
on regularly. The principal work since March last has been 
the examination of the ova and larvze of fishes. Endeayours 
have been made to obtain the early stages of as many species as 
possible, and as only a few species breed at one season, con- 
siderable success has been achieved. The results of this work 
have been communicated to the Royal Society. 
_ Since the last meeting the Physical Department of the Scot- 
_tish Marine Station has been actively engaged in carrying on 
(the Thurso at three points, the Tummel, Forth at two points, 
Teith, Tweed, and Derwent) is being observed daily. _ Mr. 
florrison has continued his monthly trips to Loch Lomond and 
Loch Katrine, where he has observed the vertical distribution 
of temperature. The work on the Firth of Forth, usually carried 
on solely by serial temperature observations made on the A/edusa 
inside the Isle of May, has been supplemented by the captain of 
one of the Granton steam-trawlers, who was supplied with a deep- 
sea thermometer, and has been using it to good purpose in the 
North Sea fron 30 to 60 miles off shore. ‘The tidal variations 
of salinity in the estuary of the Forth were investigated by Dr. 
Mill and Mr. Morrison during a week’s stay at Kincardine, and 
the result embodied in a paper read to the Royal Society of 
Edinburgh. Two trips of the A/ed@usa on the Clyde supplied 
data for a paper which is presented to this meeting, as well asa 
quantity of observations not yet fully worked up. 
The work of collecting and discussing the sea temperatures 
around the coast of Scotland is being carried on by Dr. Mill 
and Mr. Morrison. Since last meeting the Meteorological 
Council of London has lent all the sea observations made at the 
Scuttish Coast-Guard Stations from 1879 to 1885 ; and observa- 
tions of river temperature made by direction of the Duke of 
Sutherland and Mr. Boyd, Peterhead, have also been received. 
The Government Grant Committee of the Royal Society of 
London has given a grant of 50/. towards the completion of 
this work. Thermometers have been lent for use in the deep 
water off Shetland to Mr. F. Coulson, who is at present on a 
dredging trip in his yacht in that locality. The National Fish 
Culture Association of England, which has been in correspond- 
ence with the station for some time as to physical observations, 
has now commenced operations at several light-ships and on 
board the mission-smacks in the North Sea. 
Mr. John Murray, of the Challenger Expedition, made a com- 
munication on the extent of the areas of the different mean 
annual rainfalls over the globe. He had been led to undertake 
this inquiry so as to find out the amount of material carried 
down from the land to the ocean, and which went to form ocean 
deposits. The amount of rain that fell upon the surface of the 
globe annually was estimated at about 34,000 to 35,000 cubic 
miles. Taking the inland drainage areas disconnected with the 
sea, such as the Sahara Desert, it is found that 77 cubic miles of 
rain fell upon these surfaces, which must be regarded as equi- 
valent to the amount of evaporation. The Americans had 
calculated that 99 million millions of cubic feet of rain fell 
annually over the Mississippi drainage area. Calculating the 
outflow of the river, they estimated that only one-fourth of that 
water reached the ocean. By extending their inquiry over large 
areas, it was hoped that it would be made of some practical 
importance. 
Dr. H_ R. Mill, of the Scottish Marine Station, read a:paper 
on the temperature of the water in the Firth of Clyde and its 
connected lochs. The configuration of the water system was 
explained by means of a bathymetrical chart. Roughly speak- 
ing, the Firth of Clyde contained two tracts of deep water—one 
in which the water is over 70 fathoms deep, running up Kil- 
brannan Sound, and the other rather deeper between Arran and 
Ayrshire—uniting with the first at the north of Arran, and 
continuing up Loch Fyne to near Ardrishaig, attaining its 
greatest depth off Skate Island, near Tarbert, where it is 107 
fathoms. ‘hese tracts of deep water are separated from the 
Atlantic by a broad plateau, which extends between the Mull of 
Cantyre and Girvan, and rises to within 25 fathoms of the 
surface. There are also three shallow lochs—Gareloch, Holy 
Loch, and Loch Ridden ; and four deep lochs—Upper Loch 
Fyne, Loch Goil, Loch Strivan, and Loch Long—which are 
shut off from communication with the outside waters by barriers 
rising in some cases to within a few fathoms of the surface. Dr. 
Mill then gave an account of the temperature in each of the 
regions as were ascertained during trips of the AZedwsa in April 
and June. He omitted, he said, discussing in detail the indi- 
vidual observations until fuller investigation gave the data for a 
general theory. In April, surface temperature over the whole 
Clyde district varied only from 42° to 45°, and the temperature 
at considerable depths had a range of not more than half a 
degree—41°°3 to 41°°8. The warmest water was found on the 
barrier plateau at the south end of the firth, and outside it, the 
deep lochs came next, and then the deep open basins. In all 
cases the temperature fell gradually, proceeding downwards for 
about 10 or 15 fathoms, and then remained constant to the 
bottom. By June a considerable heating of the surface-layers 
had taken place, and the different regions had undergone changes 
to a very different extent. The shallow lochs had been heated 
apparently from the surface and from the bottom ; the greatest 
rise in temperature was found beyond the plateau, then in the 
deep open basins, and the least in the deep lochs, one of 
