MR. A. W. PRESTON ON THE GREAT FROST OF 1890 — 91 . 193 
the frost began to show signs of breaking up, but before it left us 
it gave us one more very sharp “ nip,” under rather unusual 
circumstances. On the 19th, which Avas a brilliantly clear day, 
the thermometer at nine a.m. stood at 2G degrees, it subsequently 
rose to 32 degrees, but in the afternoon the temperature fell with 
extraordinary rapidity, and at four p.m. stood at 15.G degrees in 
the screen and G degrees on the grass ; an hour later some cirro- 
cumulus clouds worked up from the west, and the temperature 
rose 5 degrees. There was hardly any frost during the succeeding 
night, and on the following day there was a gale from the south- 
west with rain, and it was thought that the frost had left us; but 
the next morning the roads, which had been running streams the 
provious night, were covered with a sheet of ice ! On the 23rd 
thero was a complete break-up of the frost, and during the 
remainder of the month, and the first fortnight of February, there 
was hardly a frosty night, and the mean temperature was some- 
what above the average. 
The mean maximum temperature of the entiro period was 
35 degrees, which was 1.5 degrees higher than in London. This 
is accounted for by reason of the dense' fogs which prevailed in the 
metropolis in December on many days when wo were enjoying 
bright sunshine. As an example, on December 19th the ther- 
mometer in London did not exceed 19 degrees, and a very dense 
fog prevailed all day, whereas in Norfolk there was no fog, and 
the temperature rose to 30 degrees, or 11 degrees higher than in 
London. During the frost the maximum temperature only rose 
above 40 degrees on seven days ; and from December 9th to 
January 20th (a period of forty-two days) it did not once touch 
40 degrees, an almost unprecedented occurrence. The mean 
minimum temperature of the period was 24.5 degrees as against 
25 degrees in London, and the exposed radiation thermometer on 
the grass gave an average of 4.4 degrees lower. 
At the end of this paper will be found a comparative table 
showing the principal features of the late frost, and that of the 
most remarkable ones of the present century, which was compiled 
by Mr. Charles Harding, F. R Met. Soc. ; and I have added to it 
my own figures from Blofield, which it will be seen agree very 
nearly with the London values, except as to the maximum readings, 
which differed from the causes I have already pointed out. One 
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