18 



Description of an Automatic 



The following curve of pressure and copy of the printed 

 results, from May 11th noon, to May 12th noon, will show 

 what the machine is capable of doing. 



The curve is rather a remarkable one, from the fact that 

 apparently there was but little atmospheric disturbance at 

 this place. It shows, however, that the atmosphere was 

 in a violent state of agitation, from 3 p. m. of the 11th, to 

 4 a. m. of the 12th. 



During the afternoon of the 11th, the weather was very 

 changeable ; clouds were continually passing over the 

 heavens. At 6 p. m. it began to rain, and continued with 

 intervals of intermission until some time after midnight. 

 During the afternoon and evening, the wind blew rather 

 strongly from the southwest, but was at no time very 

 violent here. 



But at other points 200 miles to the east and south of 

 this city, the wind blew a tornado, doing considerable 

 damage to property. At New York, it was most violent 

 between 6 and 7 p. m. 



The following is a/ac simile cop} 7 of the record as printed 

 by the machine. The numbers on the left hand are the 

 hours from noon of the 11th to noon of the 12th. The 

 remaining figures are the barometrical heights expressed 

 in thousandths of inches. 



