be 
ARTIFICIAL SEA-WATER. 247 
compounds in solution, and in the proportions given, from which it will 
Grains Grains 
per Gal per Gal 
Sodium chloride .............- 18941 Magnesium nitrate ..........6. 03 
Potassium chloride............ 53°6 Sodtampnitrate: de «acetescct den 02 
Magnesium chloride .......... 256°6 ORIEL ALON ciwewaded sieerneeme O1 
Magnesium bromide .......... 2°0 SUIGH, ierdes fan sia ticlastels nema aee ene 10 
Magnesium sulphate .......... 160°7 Todide of Sodium.............. traces. 
Calcium sulphate............6. 98°4 Ammoniacal salts and organic \ slight 
Calcium carbonate ............ 5'8 PELL OT Vsjaleinte/ntarpiets sl aselele eierers traces. 
Magnesium carbonate ........ 1'5 
For the thorough admixture of the water in the various tanks, and 
the preparation and filtration of solutions, a considerable length of time 
was required; and it is only at the present date that the water is assum- 
ing what may be termed its permanent and representative character. 
Time will prove how far the sanguine anticipations of its promoters will 
be realised; so far it is certain that all animals hitherto placed in 
the tanks, under fair conditions, have done exceedingly well. 
a SET VAL OR. iG NAT. Ss 
BY F. T. MOTT, F.R.G.S. 
On the evening of September 1st, between six and seven, after a 
fine, sunny day, the sky being clear, and the full moon just rising as the 
sun went down, there was a grand festival among the gnats. Above the 
tops of trees and hedgerows in the low meadows north of Leicester 
these little Diptera were out in immense numbers. I calculated that 
there might be about three millions of them to a mile of hedgerow. They 
assembled in groups of various shapes, sometimes a vertical column from 
6ft. to 20ft. high, and 1ft. to 3ft. diameter, rose from a tree top like a 
pillar of smoke. Sometimes a sheet 4ft. or 5ft. high and 10ft. long hung 
above the hedgerow, but seemed never more than a foot or so in thick- 
ness. The following evening, at the same hour, the sky being more 
clouded, a few gnats only were to be seen; but on the evening of the 6th, 
with the sky again cloudy, there was a still more remarkable display of 
gnat life. The little creatures were out again in millions, but this time 
the vertical column formation was adopted by nearly the whole of them. 
These columns rose from the hedges on either side of the road, and were 
visible for half a mile a-head at irregular distances, averaging, perhaps, 
12ft. or 15ft. They formed an avenue of such a singular and unusual 
appearance that everyone who passed along the road paused at intervals 
to watch and wonder at them. This piece of road is about half a mile 
long, on the top of an embankment which carries it over the low 
meadows and the river. At the farther end there are a number of 
trees, and from the top of nearly every tree three or four of the strange, 
smoke-like columns could be seen standing up in the air, always straight 
but not always vertical, some of them being inclined at small angles. Tt 
was altogether a very curious sight. It has not occurred again, and I do 
not remember to have seen anything like it before. 
