458 THE BOTANY OF BERMUDA. 



sustained liigli temperature of the winter, which is such that the tem- 

 perature of the soil six inches below the surftice was never found lower 

 than 520.66. 



Frost is nearly, but not quite, unknown. There are but two well 

 authenticated cases on record. On the 24th December, 1840, while 

 frost was visible " in low situations, water in tubs was frozen to the thick- 

 ness of half a crown."* On the 21st February, 1878, a thermometer 

 on grass registered 28^.2. There is a tradition of snow, about 1811 or 

 1812 ;t a few flakes, indeed, fell at St. George's on the 4th March, 1874. 

 On 20th February, 1872, the ground was in some places white with hail, 

 which did not disappear for some hours. These facts are sufficient to 

 show that the temperature of the air is subject to much greater ex- 

 tremes than are experienced at sea level within the tropics, although 

 the vegetation i^artakes so largely of a tropical character. 



Low temperatures occur most frequently in the month of March. 

 During the yesirs 1872-'77 a thermometer on grass registered below 

 40O F., as follows : 



In December 2 times, lowest 3o°.2 in 187G. 



In January 4 times, lowest 34°.0 in 1874. 



In February 3 times, lowest 35^.0 in 1877. 



In March 8 times, lowest 35^.0 in 1877. 



Notwithstanding many years of observation, the data for determining 

 4^he mean temperature of the air are imperfect. Observations have only 

 been made at 9 or 9^ a. m., and at 3 or 3J p. m., and the diurnal low for 

 the several months is unknown. While the record was kept by the royal 

 engineers, however, a monthly term day of hourly observation was ob- 

 served, and from the days so recorded some approximation to the horary 

 -corrections might probably be derived, but I prefer to give the actual 

 observations at those hours, subject to future reduction. To these are 

 added in the subjoined table the mean temperature of the soil at 6 

 inches and 12 inches depth, which will have future value, the Interna- 

 tional Meteorological Congress held at Eome in April, 1879, having re- 

 solved to include for the future the temperature of the surface of the 

 *arth among the meteorological elements to be observed. 



*Mr. J. L. HurdiH, in Jones' "Naturalist in Bermuda." 



tMr. John Harvey Darrell is the authority for this statement. 



