HERTFORDSHIRE NATURAL HISTORY SOCIETY. 
XI 
The erection of flood-marks afforded information especially 
valuable to engineers, and should be advocated by all natural 
history societies. The work might be easily done, but he did not 
think there were more than 500 or 600 such marks in this country. 
He did not himself know of 100. He felt sure that if there were ten 
times that number, they would prove extremely useful, especially 
to corporate bodies. A mere cut in a brick wall with the date and 
a horizontal line was good; if cut in a special stone, it was better; 
but engraved on a brass plate sunk in a stone was the best of all. 
The two following are on brass plates on the side of a door at 
"Warrington :— 
St 
ST THOMAS BAY 
S within 
1837 
1828 
WATER MARK 
Another in the same town runs :— 
H. W. 1828 
The lecturer preferred :— 
July 
1875 
■X 
but considered the precise form to be immaterial. 
The question of determining the height of water in wells had 
received very little attention up to the present time, and the plan 
of recording temperature in wells should be more generally adopted, 
as it gave most useful information. 
In the earlier part of his notes he had referred to whirlwinds, and 
expressed the opinion that if a whirlwind came across London in a 
certain direction, the roof of Charing-Cross Station would be carried 
into the Strand. When whirlwinds did come across the country, 
they were extremely narrow, whilst their track was seldom long. 
What was wanted was to get all the information they could as to 
the direction in which they travelled. Then there was the power 
of the whirlwind, and people would scarcely credit what tremendous 
force there must be when a whirlwind passed along. He had seen 
slates from a roof carried some distance and then driven into a tree, 
and sticking into it like the blade of an axe, and slated roofs 
weighing many tons transported bodily. 
Some people did not believe in showers of frogs and showers of 
fish, but they were quite true and easily explained. For instance, 
a few years ago a heavy whirlwind passed near Banbury, and in 
one of the ponds there, nearly every drop of water, together with 
the fish, was whirled into the air, carried some distance, and then 
dropped on a grass field. 
The altitudes of the country were being now ascertained, and 
before long the Ordnance Survey of England would be finished. 
They had a great many railroads and canals in England, and their 
