1864] Mr, RsLvtnu^— Record of the Storm of Dec. 3, 1863. 109 



II. " On the Great Storm of December 3, 1863, as recorded by the 

 Self-registering Instruments at the Liverpool Observatory By 

 John Hartnup, F.U.A.S., Director of the Observatory. Com- 

 municated by General Sabine, P. U.S. Received January 21, 

 1864. 



[This Paper is accompanied by a diagram, which is deposited, for reference, 

 in the Archives of the Royal Society, and of which the author gives the 

 following explanation.] 



The accompanying diagram exhibits the strength and direction of the 

 wind, the height of the barometer, and the rain-fall for three days pre- 

 ceding, two days following, and during the great storm of December 3, 

 1863, as recorded by the self-registering instruments at the Liverpool Ob- 

 servatory. The barometer-tracing is a facsimile of the original record pro- 

 duced by King's self-registering barometer; the force and direction of the 

 wind and the rain-fall have been taken from the sheets of Osier's anemo- 

 meter and rain-gauge ; the time-scale for the anemometer has been slightly 

 increased to adapt it to that of the barometer, and the scale of wind-pres- 

 sure for each five pounds has been made uniform, instead of leaving the 

 spaces greater or less according to the strength of the springs as in the 

 original record. The tracings of the recording-pencils for the direction of 

 the wind and the rain-fall are faithfully represented, but it is scarcely 

 possible to copy the delicate shadings and every gust recorded on the 

 original sheets by the pencil which registers the force of the wind ; all the 

 heavy pressures are, however, correctly represented, and may be taken from 

 the diagram as accurately as from the original sheets. The figures at the 

 bottom of the diagram show the readings of the dry- and wet-bulb 

 thermometers and the maximum and minimum thermometers as recorded 

 at the Observatory during the six days ; the wet- and dry-bulb thermo- 

 meters were read each day at 8 and 9 a.m. and at 1, 3 and 9 p.m. ; the 

 registering dry thermometers were read and readjusted each day at 1 p.m. 

 The time marked on the diagram for all the instruments is Greenwich 

 mean time. 



For four days previous to the 30th of November the barometer had been 

 high and steady, the readings ranging from 30'13in. to 30*33 in., the 

 latter at noon on the 29th being the highest ; from this time to midnight 

 the fall was slow and pretty uniform ; from midnight November 29 to 

 midnight December 5 the changes of barometric pressure, the strength and 

 direction of the wind, and the rain-fall are shown on the diagram. The fall 

 of the barometer on the day of the great storm was rapid from midnight to 

 6 a.m. ; heavy rain and hail fell from 3*^ 30'^^ to 7^ 20°^ ; and from 5^ 50"^ to 

 6^ 45"" it was nearly calm, during which time the wind shifted from E. 

 through S. to W. Between 6*^ 45™ and 8^ 15°' the pressure of the wind 

 increased from to 16 lbs. on the square foot, and at about twenty-five 



