84 
REPORT—1850. 
Dates and Moon’s 
age at 2o0’clock 
p.m, 
1849, June 24 
(4 days). 
1850, July 16 
(7 days). 
On the Causes of the Rise of the Isothermal Lines (as represented on Professor 
Dove’s Maps) in the Winters of the Northern Hemisphere. 
Hopkins. 
In the winter of the northern hemisphere, when the continents of America and 
Europe are cooled down to a low temperature, as shown by the isothermals for the 
: 
* See, in this Report, Mr. P. Clarke’s account of “ some extraordinary electrical appearances 
Max, of 
therm. at 
Chiswick. 
ο 
89 
89 
Remarks. 
Maximum for the year. On the 26th of July (a little more 
than a lunation afterwards) London was visited with another 
thunder and hail-storm more violent than any that had oc- 
curred there for many years, although not so destructive of 
property as that of the Ist of August 1846. 
Maximum for the year at Chiswick and Greenwich. 
The thermometer at Brighton was 80° on the 15th, and very 
high also on the 16th and 17th. At Penzance it was re- 
markably sultry on the 15th, and the clouds, a little before 
noon, gathered there from the south, as if a thunder-storm 
were approaching, and it rained most of the afternoon. 
Bristol, that afternoon, was visited by a terrific thunder- 
storm. On the following day (16th*) equally fearful thun- 
der-storms occurred in Lancashire, and atChatham and Ro- 
chester; and ‘‘ several houses in Orleans were nearly de- 
stroyed by a waterspout.”” On the 17th similar thunder- 
storms were felt at Brighton, Reading, Guildford, and 
New Galloway, at which last place there was at the 
same time a waterspout (described with a woodcut in the 
‘Illustrated London News’ of the 27th of July). Onthe 
night of the 18th a terrific storm of wind and rain from the 
east was felt on the Atlantic shores of the United States, 
greater than any there for half acentury. During all these 
thunder-storms, which have proved unusually severe and 
fatal, the rain is described as of almost unexampled violence 
and descending like waterspouts. 
On the 19th of May (two lunations before) the thermo- 
meter at Chiswick was at 72°—higher than it had been pre- 
viously for the year, and it did not exceed that elevation for 
ten days afterwards. 
On the 18th of April (the day before the moon’s first 
quarter) the thunder and hail-storm at Dublin was the se- 
verest remembered there. This was a warmer day in Mounts- 
bay than any previously for the year, and for twenty-three 
days after, the atmosphere in the evening being in a highly 
electrical state. In London, for the week ending the 19th|_ 
of April, the thermometer on every day was higher than the 
average of the same day for the last seven years, and the 
mean temperature of the week was 48°°9, beirig 3° beyond 
the average. In Scotland the air was equally sultry on the 
18th, 19thand 20th. On the 20th, 10,000 trees were rooted 
up by a storm at Strathspey in Invernesshire, and on the 
same day was a dreadful thunder and hail-storm at Dorking 
in Surrey. 
at Manchester on the 16th of July, 1850.” 
By Tuomas 
