VOL. XXVI.] PHILOSOPHICAL TRANSACTIONS. 533 



plied such a callus, that the part is not a quarter of an inch shorter than the 

 other side ; and the person is as strong as ever, and walks without any lameness. 



An Account of the Great Frost in the fVinter of 17O8 and 17OQ. By the Rev, 

 fV. Derham, Rector of U/jminsterj F. R. S. N" 324, p. 454. 



I believe this frost was greater, if not also more universal, than any other 

 within the memory of man. The longest which has happened within our me- 

 mory, was that in l683 ; but the late frost, although of shorter continuance, 

 was more intense than that ; of which I have already given some account in 

 N° 321. My thermometer was much lower on December 30, than it had ever 

 been since i6q7i when I first began my thermometrical observations; and 

 the thermometer in our repository, in Gresham- College, was lower than ever 

 it was before. The particulars of its greatest descents are these ; January 20, 

 1696, 41 degrees; January 5, l683, 40 degrees; and January 3, 1709, 43 

 degrees : and lastly, in Mr. J. Patrick's thermometer, in London, the spirits 

 were 4 or 5 degrees lower than in l683. 



In London the greatest contraction of the spirits was on January 3 ; which 

 was also an excessive cold day at Upminster ; but the greatest contraction at 

 this last place, was on December 30. The reason of the difference is, because 

 my thermometer is always abroad in the open air, where no sunshine touches 

 it ; but those two London glasses are within doors, in rooms where no fires are 

 made. And it is easy to perceive that the frost does not presently exert its 

 greatest force within doors ; and when it does, neither does it so soon abate its 

 force within doors, as without. These observations of the intenseness of the 

 cold with us, I have received confirmations of from other places in the southern 

 parts of our island. I observed, that the descent of the spirits in my thermo- 

 meter on December 30, was within ^V of an inch as great as the descent 

 effected at another time (and that in a cold day too) with artificial freezings, 

 performed both with snow and salt, and also snow and spirits of wine, each of 

 which I have several times tried, and find them nearly of equal power. It is 

 well known that we can in summer freeze with ice and salt, and the same may 

 be then done with sal ammoniac dissolved in water ; but we cannot produce so 

 intense a frost then by these means, as in winter, and especially in a very cold 

 day. 



But though the frost was so extremely rigorous in the southern parts of our 

 isle, yet the northern felt little of it, but like other winters ; as I have been 

 certified by persons that have come from thence, as well as by several letters 

 from such parts. One is from the Bishop of Carlisle, dated Rose, Nov. 5, 1 709. 

 " In January last, says he, I had a sufficient opportunity of observing the frost 



