64 NOTES ON THE PROLONGED FROST, 189O-91. 



which he bequeathed to the Royal College of Physicians, all perished 

 in the Great Fire in 1666. Almost equally sad is it that his portrait, 

 painted in oils, which he himself presented to the Schools' Gallery 

 of Oxford, has disappeared. It is believed to have been destroyed 

 as rubbish forty years ago. Only a steel engraving, made in 1796, 

 which differs from the original picture in several details, remains to 

 witness to the scholarly features of the great doctor. The engraving 

 in reproduced in the plate (frontispiece to the volume), which 

 accompanies this paper. 



His residence in Colchester still stands, and his tomb in the 

 church of Holy Trinity still proclaims over his ashes the virtues 

 which he practised whilst living." But his memorial remains in his 

 magnetic and electrical discoveries. His reputation is enshrined in 

 the science which he founded—" shining in an eternal sepulchre." 



NOTES ON THE RECENT PROLONGED FROST, 



1890-91. 



By JOHN C. THRESH, D.Sc, M.B., F.R.,Met.Soc., etc. 

 [Read March 2ist, iSgr.] 



'T^IIE following brief notes upon the recent prolonged frost are based upon the 

 -*- daily observations taken at the Climatological Station, Chelmsford, which 

 is in my charge. 



For the last few days in November and the first two days in December the mean 

 temperature was below freezing point and about five inches of snow fell. From 

 the 3rd to the gth December the mean daily temperature was above 32° F. and all 

 the snow rapidly disappeared. The prolonged frost set in on the loth, when the 

 mean temperature fell below freezing point and remained constantly below until 

 January 13th, that is, for a period of thirty-three days. On the latter date the 

 temperature rose to 33^9 and remained over 32° until the i6th. It then fell 

 and remained low until the 20th, when it again rose and the thaw set in. With 

 this slight intermission, therefore, the frost lasted forty-one days, or one day only 

 short of six weeks. 



The coldest day was December 22nd. On this day the minimum temperature 

 was 4-3, the maximum 30-5. At 9 a.m. the thermometer stood at T9- The mean 

 temperature for the day was only 17-4. The subjoined chart is interesting as 

 showing at a glance the minimum temperature and the mean dail}' temperature 

 throughout the whole period of frost. 



Snow fell on eleven days. The heaviest fall was on December i8th, when a 

 depth of three inches was registered. The snow attained its greatest depth on 

 the 30th, where there was between five and six inches on the ground. On January 

 20th rain fell ("27 in.) the temperature rose and the snow disappeared. The total 



3 The best drawing and description of the tomb, with its numerous coats of arms, and some 

 account of Gilbert's family, will lie found in Chancellors "Ancient Sepulchral Monuments of 

 Essex, pp. 202-6, pi. Ixvii.— Kd. 



i 



