200 
Gardeners and Florists’ Annual for 1918 
for beginners; it also insures a standard length in all grades. The 
measure is of wood tapering to 1 inch wide at the top; the bottom has 
a brass plate screwed on Si/g inches wide by 1 % inches deep. Any Rose 
which measures below the cross (X) marks goes into the lower grade. 
The A. T. Stearns Lumber Co. of Neponset, Boston, Mass., will 
supply one of these measuring devices to any Rose grower on request. 
Rust from Steel, Removing. — Considerable diflSculty is often 
experienced in removing rust from steel. The simplest method is to 
cover the steel with sweet oil which should be well rubbed in, and next 
day rub with finely pulverized unslaked lime. 
Scum on Ponds. — Sometimes ponds, either ornamental ponds or 
those for an irrigation supply, get covered with a scum growth. This 
may be owing to the presence of floating algae or similar vegetation. In 
those cases where much growth occurs, like that of Flannel Weed, men 
may have to wade and cut this from the bottom by means of scythes. 
There also exists a weed cutting machine, an English patent, where 
scythe-like blades are fastened to the stern of a boat and are operated 
by a scissors motion. If Duckweed, Canadian Waterweed (Elodea), 
or Azolla form a surface growth, this can be removed by meeins of 
drag nets, or strips of burlap or canvas weighted at one edge, and 
dragged right across over the surface of the water. Another means of 
purifying such ponds, which was originally recommended by the 
authorities at Kew, London, but where no fish are in the water, or where 
it is not for drinking or other use, is to place 1 lb. of copper sulphate 
in a loosely-woven sack which should be dragged through the water in 
lines at a distance of about 4 yds. apart. It is usually necessary to 
apply the copper sulphate (which is a dangerous poison, be it noted) 
two or three times between April and October. The amoimt of copper 
sulphate for use depends on whether the water is running or partially 
stagnant. One pound of this material is generally recommended, al- 
though 2 lbs. to 3 lbs. are sometimes employed. For a large pond, 
tow the bag or bags behind a boat, and row to and fro in parallel 
paths. Ordinary commercial sulphate is effective and should be broken 
small. Another practice is to spray the surface of the water with a 
weak solution of sulphate of copper, using one part or portion of this 
to from 750,000 to 1,000,000 parts of the water in the lake. No water- 
fowl should be about. To discover the cubical contents of the lake 
multiply the average width and breadth by the average depth of the 
water. A cubic foot of water weighs 62.32 lbs. Lumps of imslaked lime 
have also been recommended as a preventive of growth, these being 
simply thrown into the water from time to time. No fixed quantity 
can be recommended. Gold-fish help to keep a pond clean. 
Scum on Soil. — Green algae often covers the soil in benches and pots 
and even out of doors, with a green surface scum, which is unhealthy for 
the plants and does not look well. This can be removed by scraping 
and by stirring the soil. It is usually proof, however, of a water- 
logged or badly drained, cold condition of the soil, and good drainage 
must be established before the trouble can be thoroughly eradicated. 
Heavy soil that holds much water is also subject to green scum. Dust- 
ing the surface with quicklime is recommended, as this sweetens the 
soil and kills the green growth. Further than these precautions little 
can be done. 
