TRANSACTIONS OF THE SECTIONS. 49 
a magnet be brought near the north pole of the needle, the streams on 
that side are intercepted by the magnet, while the streams on the op- 
posite side attract the needle with the appearance of its being repelled 
by the magnet; or, if the south poles be brought near, they appear to 
repel, by the diverging streams being attracted in opposite directions 
to gain their equilibrium ; but the opposite poles attract each other by 
the streams from the south pole of the one being attracted by the north 
pole of the other magnet. 
The probability that magnetism is owing to the passing of some 
fluid through the magnet, is shown by the fracture of the magnet or 
by magnetizing a ring, which shows no signs of magnetism until pales 
and which again disappears on the broken parts. being brought into 
contact, which is explained by supposing the fluid to circulate within 
the ring, and therefore no magnetism can be exhibited till the line of 
continuity be broken. 
The author supports his opinion by general reference to the obser- 
vations on the aurora, &c., in the Appendix to Captain Franklin’s 
Journey to the Polar Seas, and concludes with proposing the experi- 
ments of raising electrical conductors to the height of the clouds in 
the frigid regions during the frosts in winter, which in his opinion 
would cause the aurora to be exhibited, and lead to important discove- 
ries in the science of magnetism. 
Observations on the Tides in the Harbour of Glasgow, and the Velocity 
of the Tidal Wave in the Estuary of the River Clyde, between Gilas- 
gow and Port Glasgow. By Wit.1Am Ba tp, F.R.S.E., MRLA., 
&e. 
The first series of observations made on the tides was commenced 
the 26th of April, 1839, and extended to the 1st of October, 1839 ; it 
‘has been tabulated, and contains 158 observations of the rise and fall 
of the tides. It is necessary to observe that during the first portion 
of the time these tide observations were only made during the day, 
and did not extend to the night tides. These 158 observations assign 
a mean rise and fall of tide in the harbour of Glasgow of 6 feet 7:20 
inches. 
The number of tide observations made from the 1st of October, 1839, 
to the 27th of August, amounts to more than 1200. These are tabulated 
and divided into months, but such of the tides as have been much dis- 
turbed by floods have been rejected. 
The mean rise and fall of these 1213 tides, assigns an average of 
6 feet 8°98 inches. 
Mr. Bald presented tables in which were contained the principal 
results arrived at, by comparing the periods of new moons, first quarter, 
full moon, and last quarter, and diagrams representing the observations 
in a continuous line. He has also drawn out eight sections, showing the 
perpendicular rise and fall of the tide for every fifteen minutes in the 
harbour of Glasgow, at Clyde Bank, ‘alias Bay, and Port Glasgow. 
1840. 
