ATMOSPHERE. 



ATMOSPHERE. 



TATION.) The composition of the atmosphere 

 is always the same, although it has been ana- 

 lyzed when obtained from the most elevated 

 mountains, the lowest marshes, from crowded 

 cities, and the surface of the ocean, in all 

 winds, and in all states of the barometer. 



The following table exhibits the atmosphe- 

 ric mean temperatures in various parts of the 

 United States and Territories, not only for the 

 whole year, but for each month. It is abridged 

 from Dr. Forry's Treatise upon the Climato- 

 logy of the United States. The mean tempe- 

 ratures of some other celebrated places in the 

 old world, are subjoined for the purpose of 

 comparison. 



The mean temperatures of the various mili- 

 tary posts, are the results of 90 observations 

 for each month, and 1095 for each year. The 

 rule followed for computing the mean, was that 

 adopted by the regents of the University of 

 New York, viz.: Take the lowest morning 

 temperature, the highest afternoon tempera- 

 ture, and the temperature an hour after sunset. 

 The mean of these observations for the day is 



found, by adding together the first, twice the 

 second and third, and the first of the next day, 

 and dividing the same by six. To most common 

 observers this will appear rather an intricate 

 mode of attaining an object which is so con- 

 veniently, and, in general, so satisfactorily ac- 

 complished by the very simple process of 

 dividing the sum of the highest and lowest ob- 

 servations during the day. Strictly speaking, 

 the mean temperature of a day is equal to the 

 sum of the temperature observed by the ther- 

 mometer every hour or every minute, divided 

 by the number of hours or minutes in the day. 

 The hourly changes of atmospheric tempera- 

 ture have actually been observed for a con- 

 tinued year in some instances, among which 

 we may mention that at the Arsenal at Frank- 

 ford,, near Philadelphia, in the year 1835 6, 

 conducted under the superintendence of Capt. 

 Mordecai, of the United States army. The 

 results of these hourly observations are pub- 

 lished in the 19th volume of the Journal of the 

 Franklin Institute, New Series. 



For further information relative to weather, 

 and atmospheric conditions in general, see BA- 

 ROMETER, CLIMATE, TEMPERATURE, &c. 



ATROPHY. In farriery, a morbid wasting 

 and emaciation, attended with a great loss of 

 strength in animals. 



AUGER, BORING. An implement for bor- 

 ing into the soil. An auger of the above kind, 

 yhen made of a large size, and with different 

 pieces to fix on to each other, may be very 

 usefully applied to try the nature of the under 

 soil, the discovering springs, and drawing off 

 126 



water from lands, &c. In order to accomplish 

 the first purpose, three augers will be neces- 

 sary ; the first of them about three feet long, 

 the second six, and the third ten. Their diame- 

 ters should be near an inch, and their bits 

 large, and capable of bringing up part of the 

 soil they pierce. An iron handle should be 

 fixed crossways to wring it into the earth, from 

 whence the instrument must be drawn up as 

 often as it has pierced a new depth of about six 

 inches, in order to cleanse the bit, and examine 

 the soil. 





