APRIL 22, 1897 | 
NATURE 
395 
+ 300 scale divisions, equivalent to 6°2 volts, to begin with in 
each case. 
28 y 
Bee é 
GaSe : 
FI isso Leakage in R lee 
ame. a c im 5 two minutes. emarks. 
025 
G53 8 
=P 
Centi- Scale 
metres.| divisions. | 
Spirit flame | 66 | 292 pos. | Funnel of 15:3 cm. bore all 
vertical. 
” ” 287 neg. 2? ” ” 
” | 112 | 253 pos. 2 ” » 
bi} | ” 254 neg. 22 ” ” 5 
( Funnel 114 cms. vertical 
5s 343 22 pos. of 15°3 cms. bore; and 
40 Be 20 neg. 229 cms. horizontal of 
3°8 cms. bore. 
Same vertical, and 122 cms. 
4 236 pe bos: horizontal of 3°8 cms 
20 neg. | } 3 ‘ 
2? » |{ bore. 
‘Same vertical, and 46 cms. 
I O pos. | . 2 
aa 5 pe I \J horizontal of 3°8 cms. 
ob) 2 40 neg. | bore 
| ( Same vertical, and 130 cms. 
«, | f Same vertical, 
74 Br) 205 Po horizontal of 15°3 cms. 
” ” 187 neg. | | bore. 
Charcoal 3 54 pos. | » oH ” 
33 ”? 57 neg. | »” ” 2? 
| 
conductive quality of the air and fumes ceased within a quarter 
of a minute. 
§ 13. In connection with these last experiments, attention may 
be directed to an experiment described by Prof, Schuster, in 
which he uses an insulated metallic tube bent round at the upper 
end, to prove that ‘itis not only the flame itself which conducts, 
but also the gases rising from the flame.” He discovers 
electric conductance in products of combustion mixed with air 
quite out of sight from the flame. ‘ 
SURVEY OF. THE TIDES AND CURRENTS IN 
THE GULF OF ST. LAWRENCE. 
\ JHEN the meeting of the British Association was held at 
Montreal in 1884, the necessity of establishing stations 
for tidal observations in Canadian waters was discussed, and the 
Association adopted a resolution drawing the attention of the 
Government of the Dominion to the matter. A committee was 
also appointed to collect information and make representations 
to the Government respecting it. Two years later a large 
deputation, representing the British Association, the Royal 
Society of Canada, and the Board of Trade of Montreal, waited 
on the Minister of Marine. The matter was favourably 
received, but, owing to financial reasons, any action was for 
the time postponed. In 1889, however, exploratory trips 
were undertaken, by direction of the Government, with the 
view of ascertaining the best points to establish tide gauges ; and 
in 1890 a practical commencement of the survey of the tides and 
currents in the Gulf of St. Lawrence was made. The object of 
this survey is to furnish data for compiling trustworthy tide-tables, 
and to afford information as to the set of the tidal and other 
currents in the Gulf. The value of such information is shown 
by the remarks of Lieut. Gordon in his report to the 
Minister of Marine, in which he expresses the conviction that 
until an exhaustive examination of the whole system of tidal 
movements carried out on similar plans to those which have 
been made on the United States coasts, and on the coasts of 
Great Britain, has been made, there will always be the liability 
to heavy maritime losses due to the lack of information. The 
average loss, he states, is now over half a million of pounds—a 
large proportion of which is due to a want of knowledge of the 
currents. 
For the purpose of determining the set and cause of the 
1 Prof. Schuster, on ‘‘ Atmospheric Electricity,” at Royal Institution, 
February 22, 1895. 
NO. 1434, VOL. 55] 
Currents, it was necessary to have a trustworthy record of the 
time and range of the tides; of the variation in the pressure of 
the barometer ; the force and direction of the wind; and the 
temperature and density of the water at different depths. The 
survey is under the charge of the Marine Department, with 
Colonel Anderson, Chief Engineer, at the head. The tidal survey 
is in charge of Mr. W. Bell Dawson, C.E. Four reports as to 
the progress ot the work have already been issued. In the first 
season the two entrances to the Gulf were examined at Belle 
Isle and Cabot Straits, between Cape Breton and Newfound- 
land ; and the general relation of the Gulf to the oceap as re- 
gards tide and currents wasexamined. Next season the entrance 
between the Gaspé coast and Anticosti was examined, and the 
nature of the currents was traced across the south-western side 
of the Gulf to Cape Breton. This part of the Gulf is a steam- 
ship route of constantly increasing importance. More recently, 
the north-eastern arm of the Gulf, from Anticosti to Belle Isle, 
through which passes all the Atlantic traffic which takes the 
Belle Isle route, has been under examination. Seven self- 
recording tide gauges have also been set up, the establishment 
of the intended stations on the Atlantic coast having been 
postponed owing to the want of funds. Although the shortest 
time for obtaining a correct computation of the tides at any port 
is the lunar cycle of nineteen years, sufficient data have been col- 
lected to enable the Department to issue tide-tables for the use 
of the pilots of the St. Lawrence, and for Halifax. 
It has been settled that the current in the Strait of Belle Isle 
is fundamentally tidal ; and, under normal conditions, runs east 
and west, with velocities of about two knots in each direction. 
During heavy winds, especially when westerly, the current which 
runs with the wind becomes stronger than the current against it ; 
and for a time the current may become continuous in the same 
direction as the wind. 
The tides vary in height from four to five feet in the open 
Atlantic, to twelve feet in the lower part of the St. Lawrence 
River, seventeen feet at Quebec, and thirty feet over the Bay 
of Fundy. To correctly observe these, tide gauges fixed at 
different parts of the coast are required. Owing to the unin- 
habited condition of a great part of the coast, the difficulty in 
selecting suitable places and attending to the gauges has been 
very great. The self-recording gauges used are of the usual 
design, but special precautioas have had to be taken to guard 
against the effect of ice and the oscillation due to wave action. 
At most stations no wharves or quays were available against 
which the gauges could be fixed. At some of the stations wells 
had to be sunk at high-water mark to the level of the lowest 
tides, and a trench, 270 feet long and 10 feet deep, excavated 
across the rock shore, to admit the tide to the well. The tide 
was led to the well by wooden piping, made from fir trees, 
twelve inches diameter, having a hole three inches in diameter 
bored through the centre, the joints being made tight with sail- 
cloth saturated with white lead. To prevent the effect of air 
entering the pipes, due to the surge of the sea in rough weather, 
an iron pipe was laid out along the bottom for about 100 feet, 
into water having a depth of twelve feet at the lowest tides. To 
prevent freezing in winter, a boiler, three feet in diameter, was 
placed vertically in the well and kept heated, and in this the 
tide pipes were fixed. These gauges have been occasionally 
damaged during gales, and in one case the station could not be 
reached between January and the opening of the navigation in 
May. At some of the stations, situated on islands, it was 
necessary to make a telegraphic exchange of time oncea week to 
regulate the driving clocks. To avoid this expense, meridian 
instruments, named dzplezdoscofes, have been employed, which, 
when once set correctly, give the exact time of the sun’s meridian 
passage. These were obtained from a Paris maker. 
The currents in the Gulf are affected both by the tide and the 
amount of fresh water coming down the river. It was found that 
the under-currents which exist are frequently displaced and 
brought nearer the surface, either by the effect of wind or by a 
variation in the temperature. For the purpose of ascertaining 
the position and force of these currents observations were 
taken as to their flow, and also as to the temperature and 
density of the water. From Quebec to Father Point the tidal 
current occupies the whole width of the river ; when the channel 
widens, a part of it is occupied by a constant downward current 
which runs parallel to the south shore all the way to Gaspé. The 
main tidal current enters the Gulf from the Atlantic by Cabot 
Strait, between Cape Breton and Newfoundland, and does not 
lose itself in the great expanse of the Gulf, but continues across 
