86 A DUST-FALL IN THE SOUTH-WEST OF ENGLAND 
weather. The dust was very fine, pinkish in colour, and of 
amount sufficient to colour the white paint.” Observers 
in Devon describe the deposit as “ a layer of cream-coloured 
sandy material,” ^ while in another locality the rain water 
as it entered the cistern was “ like water with yellow clay 
held in solution.” ^ 
The recorded rainfall at Tavistock, Devon, was 0-01 
inch on February 19, 0-15 inch on the 20th, 0-18 inch 
on the 21st, and 0-38 inch on the 22nd. ^ 
At the time of the dust-fall I was staying at Tavistock, 
and on February 21 I observed a yellow glare in the high 
fog or low cloud, while on the 22nd I was successful in 
obtaining sufficient deposit to be able to make some 
examination of it. The rain contained 38-2 grains of 
suspended matter to the gallon,and the microscope revealed 
that the deposit was an amorphous clayey matter mixed 
with round and angular fragments resembling quartz. An 
analysis was made which showed that the dust was com- 
posed of a certain percentage of organic matter which was 
mixed with ferruginous sand, chalk, and silicates of alumina, 
alkalis, lime and magnesia. The figures obtained were as 
follows — 
Per cent. 
Silica 47-62 
Alumina ........ 19-22 
Iron Oxide ....... 5-87 
Lime ........ 8-24 
Magnesia . . . . . . .2-26 
Sodium Oxide ...... 1-28 
Potassium Oxide . . . . . .2-10 
Carbonic Acid . . . . . . .6-30 
Water and Organic Matter . . . . . 7-11 
100-00 
The figures given in the following table are obtained by 
calculating the organic constituents as percentages on 
1 Mr. A. G. Manley, of Torquay, Devon. 
2 An observer at Torrington, North Devon. 
3 Mr. E. E. Glyde, F. R. Met. Soc., Whitchurch, nr. Tavistock, 
Devon. 
