156 
volume of the Botanical Magazine (30th vol. of the 3rd series), and 
Mr. Wm. Robinson a volume of “ The Garden ” with a notice and 
a portrait. In May, 1886, Mr. Maw left his old residence at 
Broseley for Kenley in Surrey, where he has lived in retirement 
and where he died on February 7th, 1912, at the age of 79. 
J. GB, 
Pond-weed and Copper Sulphate—A frequent application for 
advice made to Kew is from correspondents whose ponds or lakes 
are infested during summer by the various forms of Algae or 
“weed ” found in British waters. Zveryone knows the unpleasant 
nature of the scum-like and other growths that are nearly always 
seen at that season on still, or nearly still, water. They not only 
frequently destroy the beauty of ponds entirely for a time, but are 
offensive to the nostrils as well. A good deal of this annoyance 
may be avoided by the use of copper sulphate. Owing to the water 
of the Lake at Kew being pumped for garden purposes (including 
the watering of ferns and other low types of vegetation) it is con- 
sidered inadvisable to use copper sulphate there, but it is employed 
with advantage in the smaller ponds. e proportion used is 1 part 
copper sulphate to anywhere from 750,000 to 1,000,000 parts of 
water. It is first necessary to ascertain, approximately at least, 
the cubic contents of the water to be treated. The sulphate of 
copper should be obtained in a pulverised state, placed in a porous 
bag, and dragged through the water until dissolved. It does not 
matter how the sulphate is distributed so long as it is done 
thoroughly. It may be dissolved previously and sprayed evenly 
over the surface, provided no water-lilies or other aquatic phanero- 
gams are in growth. It may be mentioned that a cubic foot of 
water weighs about 621 Ibs. 
During the last two summers a striking example of the effective 
use of copper sulphate has been provided in St. James’s Park. 
Previously, it had been a costly and troublesome matter to keep the 
water there presentable in hot weather by employing men in boats 
to remove the weed with rakes, &c. The copper sulphate treatment 
was adopted, with the result, we learn, that at a much less expendi- 
wen money and labour it can now be kept practically free from 
weed. 
: A fact of considerable interest has also been reported by the 
Superintendent. The ponds are cleaned out triennially and the 
surplus fish disposed of. In recent years it has been found that 
. many of the fish were badly attacked by fungus, so much so that 
it became doubtful whether it was advisable to transfer them to 
other waters. We learn that at the last cleaning out the fish were. 
se free from fungoid disease and remarkably clean and silvery. 
his is of especial interest because one of the doubtful matters 
about the use of copper sulphate in water was its effect on fish. 
It has been found in America that certain delicate species were 
affected, but usually when a considerably stronger application was 
used than that mentioned above. 
W. J.B. 
