ATMOSPHERE OF GREAT BRITAIN AND ON THE CONTINENT. 623 



occasion the wind was much the same as at the time of the previous visit. In 1893 

 observations were made on two different days : od both of these the wind was south-west 

 and the numbers very high, varying from 100,000 to 150,000 per c.c. 



Bellagio. 



The observations at Bellagio were made in the end of April or beginning of May in 

 the different years. The minimum number observed was 600 in 1890, rising in 1892 

 to 1125, in 1891 to 1325, in 1889 to 2900, and as high as 3300 in 1893. The maximum 

 at Bellagio, as at the other places, is of little value, as the situation is liable to local 

 pollution. 



Baveno. 



The Baveno observations were made in the beginning of May of the different years. 

 The lowest number observed at this station was 775 per c.c. in 1891. In 1892 the 

 lowest was 1075, in 1893 it was 1225, rising to 1750 in 1890, and to 2900 in 1889. 

 Here, as at the other places, the maximum is greatly due to local pollution and sometimes 

 went high. 



At this place, in addition to the observations made at low level, an excursion was 

 made on many afternoons up the slopes of Monte Motterone to an elevation generally of 

 1500 to 2000 feet, observations being made at one or two points on the way up. During 

 the time these observations at different levels were made in 1891 there was generally 

 very little wind, and the difference in the readings at high and low level was very 

 marked. Owing to calms, the local impurities collected at low level, there being no wind 

 to carry them away, the upper air being thus kept comparatively pure. For instance, on 

 the 11th May, for an ascent of 800 feet, the number of particles fell to one half of what 

 it was at low level, the figures being 6400 per c.c. at the lake side and 2900 at 800 feet. 

 On the 12th the number fell from 3700 at the low level to 2900 at 1000 feet. On the 

 13th it was 6700 at the lake side and 3800 at 1000 feet, and down to 1900 at 1800 feet. 

 On the 15th it was 4200 at low level, and the observations at different heights show a 

 gradual fall to 1350 at 1800 feet. The lowest number observed on Lake Maggiore in 

 1891 was 300 per c.c. This low number was observed on board the steam-boat on the 

 way up the lake, immediately after a thunderstorm, and it is much lower than any of 

 the observations made at Baveno. 



The 1892 observations at different levels do not show the air at high level to be very 

 much purer than at the lake side. On the 9th, for instance, the number at low level was 

 high, being 7000, and it fell to 2500 at 1200 feet, but this was caused by change of wind ; 

 and this number was just about the same as was observed on returning to the lake side, 

 where also the wind had changed to a purer direction. The observations on the 10th 

 show a somewhat similar result. The number was high at low level on starting, being as 

 high as 6900, but it only fell to 5200 when it was first tested at 1200 feet ; but half an 



