OF ARTS AND SCIENCES. 273 



one as the most marked cold period of the season, entered the territory 

 of the United States at the point before mentioned on the 5th of Janu- 

 ary, and on the 6th reached Utah, on the 7th Santa F^, and on the 8th 

 the Gulf of Mexico, and, passing onwards, it was felt in Guatemala on 

 the 10th. While it was advancing southward, it was spreading over the 

 continent to the east ; on the 7th, it reached the Red River settlement, 

 and all places under the same meridian, down to the Gulf of Mexico. 

 It reached the meridian of Chicago on the 8th, the western part of 

 the State of New York on the 9th, New England on the 10th, and 

 Cape Race on the 13th. It moved with a'bout equal velocity over the 

 Southern States, and was observed at Bermuda on the 12th. 



The remarkable frost of last June, so far as it has been traced, had 

 the same origin, and followed the same eastward course. The fact was 

 also illustrated by the maps before mentioned, that the warm periods 

 which have occurred in past years have followed the same law of pro- 

 gression, and consequently their approach could have been announced 

 to the inhabitants of the Eastern States several days in advance, bad a 

 proper system of telegraphic despatches been established. 



The value of the telegraph in regard to meteorology has been fully 

 proved by the experience of the Smithsonian Institution. The Morse 

 line of telegraph has kindly furnished the Institution during the last 

 twelve months, free of cost, with a series of daily records of the 

 weather, from the principal stations over the whole country east of the 

 Mississippi River and south of New York. In order to exhibit at one 

 view the state of the weather over the portion of the United States just 

 mentioned, a lai'ge map is pasted on a wooden surface, into which, at 

 each station of observation, a pin is inserted, to which a card can be 

 temporarily attached. The observations are made at about seven 

 o'clock in the morning, and as soon as the results are received at the 

 Institution, an assistant attaches a card to each place from which intel- 

 ligence has been obtained, indicating the kind of weather at the time ; — 

 rain being indicated by a black card, cloudiness by a brown one, snow 

 by a blue one, and clear sky by a white card. 



This meteorological map is an object of great interest to the many 

 persons from a distance who visit the Institution daily ; all appear to 

 be specially interested in knowing the condition of weather to which 

 their friends at home are subjected at the time. But the value of the 

 map is not confined to the gratification of this desire. It enables us to " 



VOL. IV. 35 



