-, NaturaUPhiUfsophical Collections. 461 



The constitution of Urea, according to the analysis of Prout, compared with 

 one atom each of atbmonia, cyanous acid, and water, is as follows : 



Prom which we see thit the elements in both are in the same proportion ; which 



confirms the experiments of Wiihler. Yet urea is not a cyanite of ammonia, for 



stronger bases do not develope ammonia. The atoms, therefore, must have com- 



bined themselves in a different manner, so that the cyanite of ammonia, from 



being a compound atom of the second, has passed to the state of a compound 



' atom of the first order. This is one of those few examples from which we can ac- 



- curately and strictly deduce the law, that the same number of single atoms may 



t;:S combine in different ways, so as to produce bodies of very different characters and 



fproperties. — Ibid. 



Mean Temperature of the Air and of the Earth in some parts of Eastern 

 Rxissia ; by A. Kuppfeh. 

 \i 



., Afean Temperature at Casan, lat. 55° 40'. long. 47° 9'.— The observations 



• were made in the garden of the University, in the shade, under a tent erected on 



the spot, where the air circulated freely, at 9 A.M., noon, 3 P.M., and 9 P.M. 



An accident happening to the maximum and minimum thermometer, prevented 



the continuance of the observations for more than three months. 



9 a. m. noon. 3 p. m. 9 p. m. 



Mean temp. +2.0 R. -+-2.4 -f-2.5. +1.6 



Mean of the maximum and minimum in December 1828, January and February 

 1829. 

 December . — 8.7 



January . — 15.2 



February . — 15.1 



The greatest cold occurred on the 18th and 19th of January ; the corrected 

 ^spirit-thermometer was down at 31° 7* ^- A little mercury exposed to the air 

 in a bottle froze almost entirely. The greatest heat was on the 8th of July ; 

 it was +24° 8. at 3 p.m. Excessive cold is very rare at Casan, where the 

 thermometer often falls to — 25° ; the temperature of summer is sometimes +26° 

 to 27°. 



Mean of the observations. Mean from 7 a. m. to noon. 

 Mean temperature of 1814 +2.5 



1815 2.7 2.3 



1816 3.5 3.1 



1817 1.5 2.0 



.. Mean . +2.6 +2.5 



On adding the mean temperature of 1 828 = + 2 R. , we have, for the mean 

 temperature at Casan, in the garden of the University, 40 metres above the level 

 of the sea, +2.4. These observations confirm the remarlc that the mean tem- 

 'perature of October nearly equals the mean of the year, and that the mean of 

 ■April approaches it. 



The temperature of springs is obtained from those, which come from a suffi- 

 'tjient depth and with sufficient abundance not to change on contact with the air ; 



