before those in the two pots, which were not electrified, but otherwise ex¬ 
posed to some circumstances. 
It appears, say s the celebrated Cavallo, from the observations which have 
been made on the electricity of the atmosphere, that Nature makes great use 
of this fluid in promoting vegetation. 
1. In the spring, when seeds begin to sprout, then temporary electrical 
clouds appear, and pour forth electric rain. The electricity of the clouds and 
rain continues to increase, till that part of the autumn in which the last fruits 
are gathered. 
2. It is this fluid which collects the vapours, forms clouds, and is then 
employed to disorder and dissipate them in rain. It gives fire to common 
moisture, by the help of which it actuates and animates vegetation. 
3. From this principle may be explained the old proverb, “ that no water¬ 
ing gives the country so smiling a look as rain.” The clouds of rain by ex¬ 
tending their electric atmosphere to the plants, dispose the pores of the latter 
to receive with greater facility the water which is impregnated with this 
penetrating and diluting fluid. 
Yentinat in his Tableau die regne vegetal , vol. i. in confirmation of this 
doctrine, says, notwithstanding the ingenious manner in which Dr. Ingen- 
housz * has endeavo ured to overthrow the belief of the importance of electricity 
* One of the arguments used by Dr. Ingenhousz against the beneficial effects of electricity on 
vegetation, is the well known rapid growth of plants in Egypt, where there seldom appears any rain. 
It has been argued in many places of this work, that Nature is seldom prodigal; and where less sti¬ 
mulation was wanted, there the different operating agents were not found so abundant. Heat and 
moisture sufficiently combine here to produce this rapid increase, and the plentiful dews, which fall 
every evening, would at any rate compensate for the loss of electric showers. I shall take this oppor¬ 
tunity of calling the attention of my readers to a very singular production of the electric fluid, which 
is frequent in the sultry regions adjoining to the Egyptian shores. Bruce, the discoverer of the source of 
the Nile, thus describes this wonderful natural phenomenon. “ In that vast expanse of desert, from 
the west to the north-west of us, we saw,” says this traveller, “ many prodigious moving pillars of 
sand at different distances, at times darting forward with great celerity, at others, stalking on with a 
majestic slowness; at intervals we thought they were coming in a very few minutes to overwhelm us; 
and flying particles of sand did actually more than once reach us. Again they would retreat, and 
diminishing by degrees, at length disappear. The tops of these pillars seemed to reach the very clouds. 
Sometimes a separation would take place, and the pillars would become disjointed, when presently they 
dispersed in air, and appeared no more. About noon they began to advance with considerable swift¬ 
ness upon us, the wind being very strong at north : eleven of them ranged along-side of us, probably, 
at the distance of three miles. Their greatest diameter, as far as one could judge, from sight, might 
be about ten feet. These appeared at intervals during the whole of the day. As the evening was 
drawing in, and the sun was setting, they produced a superb Temple, and his rays shining through 
