qf,4^:Aqxieom Portion of the Almos,j)lierc. 429 



until one in the afternoon, when it reaches 9*511. From this 

 time it diminishes, and at 11 p.m. is only 7*863. .,^ , , 



The same writer has given the vapour pressure on ;|[he 

 coasts of the Baltic, at Trapstow near the Rya, for the months, 

 of July and August. It appears that in those parts the mini-, 

 mum pressure for July is 10"05 at two o'clock in the morning, 

 and the maximum is ll'il at two o'clock in the afternoon. 

 For August, the minimum is 11-18 at three o'clock in the 

 morning ; and there are two risings, the first until ten o'clock, 

 when it is at 12*05 : from this time it falls till two, and then, 

 suddenly rises until three o'clock, from which time it falls for 

 the rest of the day. From these statements we find that there 

 is, on the coasts of the Baltic, particularly in August, in the 

 middle of the day, a material departurp^from a single ris^, and 

 a single fall in the vapour pressure. ^'.V/g.q^.nofiijv .jdj 'tp bpr; 



There are also tables for Zurich^ and otnei* places m its 

 neighbourhood. At Zurich, in the month of June, the mini- 

 mum pressure is 10*56 at 4 a.m., from which hour it rises 

 until 8 A.M. After this it falls a little, and irregularly fluc- 

 tuates until 8 P.M., when it reaches 11*34-, having fluctuated 

 greatly during twe|y^et ho^i;i^ t;^rnelxr.,fr,9nx.§,4fM? ^^^^t^\f9^ 

 and ranged 0-78. ,^.,, yhrjod edt \^AVdi\u thiipasf) ji i\me.i>i\^ 



In September, at the same place, the mmlmum viras at 

 5 A.M., and there were two risings, with an intervening fall.. 

 The first rise was up to twelve o'clock, — four hours later than 

 the first in June; and the advance above the minimum was 

 1'73, making a greater range than that of June by 0*95. 

 Here, too, the disturbance in the middle of the day is very 

 palpable. These parts of the world are at comparatively low 

 levels, — the first named being near the sea, and the last (at 

 Zurich) an inland situation, which, though considerably above 

 the sea, is not on a mountain. 



When these observations were made at Zurich in the month 

 of June, others were made on the adjoining mountain, called 

 the Righi, 1402 metres above the Lake of Zurich. On the 

 Righi, the minimum pressure was at 5 a.m., an hour later 

 than that on the plain, being then 6*27, from which it rose 

 until noon, and reached 7*54, making a range of 1*27. From 

 this hour the pressure declined until five the next morning. 



On the Faulhorn, a mountain in the same locality, but 

 higher than the Righi by 870 metres, observations were made 

 in September, at the same time as others were made at Zu- 

 rich ; and on the mountain the minimum pressure was 3*40, 

 and occurred at 6 a.m., an hour later than at Zurich. From 

 this time it rose until three in the afternoon, when it reachedj 

 5*07, making the range in the day so much a!^,,]^'$,7i.'(|^j|s| 



