892 Transactions.— Miscellaneous. 
- Mr. W. H. Preece writes, stating his opinion that the mass of matter 
ejected retained the same electric sign as that of the earth, and as long as 
that was the case the repulsion force would be sufficient to keep the matter 
afloat: and, in reference to that theory, Mr. Crookes writes to state that with 
the rarefaction of one millionth of the atmosphere, two pieces of electrified 
gold leaf repelled each other at a considerable angle for 13 months; and 
goes on to state that that rarefaction is attained at an altitude of 62 miles, 
and that the air there is a perfect non-conductor of statical electricity with- 
out interfering with the mutual repulsion of similarly electrified particles ; 
and when we bear in mind that the particles of minute dust are many 
thousands of times smaller and lighter than the gold leaves operated upon, 
there is every reason to believe that electrified dust, even projected 50 or 60 
miles high, might remain there many years. 
Before proceeding further, I must draw your attention to the fact that at 
the time of the great eruption, and during September, the mean tempera- 
ture at Batavia and throughout Java generally is at its maximum; con- 
sequently we may conclude that the equatorial belt of calms and uprushing 
air, that encircles the globe, was lying over that district at the time. This 
uprush is caused through the heated atmosphere rising and the two trade 
winds, the north-east and south-east, feed it. When this heated air has 
reached its proper altitude, it flows off to the north and south, but the 
rotation of the earth causes it to flow towards the north-east in the north 
hemisphere, and to the south-east in the south hemisphere, and these winds 
are called by some the return trades, and by others the south-west and 
north-west upper currents respectively, and are of great altitude, probably 
ranging up to 50,000 feet. 
Well, the most bulky masses cast upward by the eruption of Krakatoa 
would immediately fall, and the less bulky would fall later, according to 
their size, but the great portion of the dust and ash would be caught, on its 
downward course, in those upper currents just alluded to, and be carried by 
them to the north-east and south-east. Such we find to be the fact, for the 
ship ** Meda,” when to the westward of Cape North-west, Australia, or about 
1,050 miles south-east of Krakatoa, experienced a fall of dust like fuller’s 
earth, which covered the vessel, on the night of the 30th-31st August. 
And Captain Tierney of the brig “Hazard” on the 1st September, near 
New Britain and New Ireland, a distance of 8,850 miles due east of 
Krakatoa, saw the coloured sun, which was no doubt due to the presence of 
dust in the atmosphere drifted eastward with the upper current. 
Now, turning to the north-east quarter, or the direction in which the 
south-west upper current of the north hemisphere proceeds, we find that in 
Japan during the 29th, 80th and 31st August, the sun was of a copper 
