213 
of the particles contained in the rain water after the long drought. 
He had intended to bring these observations before the Society 
in a complete form, but has not hitherto found time to do so. 
He proposed to carry on observations during every month in the 
year, for the purpose of recording the average amount of solid 
matter deposited on a given area, and also as far as possible to 
ascertain the character of the deposits. The observations so far 
have shown, as might have been expected, that the dust in various 
localities, at different altitudes, and under other varying condi- 
tions, contained particles differing in magnitude, appearance, and 
quantity for the same superficial area. In every instance mole- 
cular activity was abundaut, but the animal life was very variable 
in amount, the largest number of moving organisms being in the 
dust collected at the lowest points — this was about five feet above 
the surface of the earth. This dust also contained the largest 
proportion in magnitude and quantity of vegetable matter. 
These observations also show that in thoroughfares where there 
are many animals engaged in the traffic, the majority of the light 
dust, which when disturbed reaches the average height of five 
feet, or about the level of a foot-passenger’s mouth, consists of a 
large proportion of vegetable matter which has passed through 
the stomachs of animals, or which has suffered partial decompo- 
sition in some way or other. This is not an agreeable piece of 
information, but it is a fact. It shows the necessity, in a sanitary 
point of view, of the streets being well watered before the scaven- 
gers are allowed to commence operations ; otherwise the light 
dust is only made to change its locality, and is not properly 
removed. It is not pleasant to contemplate the possibility of 
germs of disease being wafted along with this decaying matter 
and inhaled by those whose condition might be favorable for its 
development. The author hopes to bring the details of these 
observations before the Society at some future time. 
H. A. Hurst, Esq., read a paper on the “ Elora of Gibraltar,” 
in which he remarked on its great richness, comprising, as it does, 
in an area of about If square miles, 500 plants, being one half of 
those contained in the ‘Cybele Hibernica,’ and one third of the 
whole number enumerated as growing in the British Islands in 
the last London Catalogue. 
Microscopic Section op the Lower Moslet Street 
Natural History Society. 
January 11th, 1869. — Mr. Chaffers presiding. 
The minutes of last meeting were read and confirmed. 
The following members brought their microscopes : — Messrs. 
Armstrong, Hope, Chaffers, Hyde, Nash, Wrigley, Jackson, and 
Wilmot. 
The following objects, amongst others, were exhibited : 
Mr. Hope — Spiracle of Dytiscus, soldier beetle, scale of eel, &c. 
