198 
Proceedings of Eoyal Society of Edinburgh. [sess. 
wind, otherwise the spray "produced by the breaking waves 
introduces a disturbing element. The place selected for testing the 
sea air was in the west bay, at the outer end of the small iron pier. 
There were no waves breaking outside of the position of observa- 
tion, and the number obtained would be correct for the air at the 
time. The number was very large, 10,000 per c.e., and when again 
tested on the beach to the lee of the breakers, which were high con- 
sidering; there was so little wind, the number was 12,000 per e.c. 
This increase on shore may have been due to particles originated 
by the waves. The very large number got at this situation would 
seem to suggest that the air had not come from far over the sea, but 
might have been land air which had circled round as the wind was 
light, or it might have been the air of the land breeze of the 
previous night returning as a sea breeze. 
Very few favourable opportunities occurred for making observa- 
tions on the air of Mentone. On the afternoon of the 25 th of April 
tests were made on a hill about 1000 feet high, situated to the 
north-west of the town. When the observations began the wind was 
from the north, that is from the mountains, and there were 1200 
jjarticles per c.c. in it. A little later the wind changed and brought 
up the air of the town, when the number began to rise, and became 
as great as 7200, and was still rising when the observations were 
concluded. 
On the morning of the 27th April I took a boat and pulled out 
to some distance seawards of the Mentone breakwater, and tested 
the air coming in from the sea. The number was 5000 per c.c. 
There was not wind enough to crest the waves. Later in the day 
the wind increased in force from the south-west, so that possibly 
the air examined in the morning may have been true sea air. 
A number of observations were made at Bellagio on the Lake of 
Como. All these tests showed the air to be very full of dust for a 
mountainous district. But during the time of my visit the wind 
always blew from the south, that is from the inhabited parts of 
Italy; and, further, it was always light, so that local impurities 
were not swept away. The tests were made at an open window 
overlooking the lake, when the wind blew towards the shore, 
and at other times they were made on the top of the hill at the 
Villa Serbilloni. 
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