8 Farmers’ Bulletin 1285. 
batch of the concentrate is to be made over an open fire, it will be well 
to start with about 60 gallons to allow for the evaporation. The 
measuring stick in this instance should have at least two notches, 
one representing 50 gallons, or the volume of the finished product,* 
and the other 60 gallons, or the volume at the start. In the instance 
of larger plants the cooking tanks can be readily marked or a float 
gauge installed to indicate the volume. 
COOKING. 
The pooling is done by actively boiling the lime and sulphur to- 
gether until they have practically gone into complete solution or, in 
other words, until the sulphur granules have all dissolved.4 Abun- 
dant experience has shown that this will require about 50 minutes of 
vigorous and continuous boiling, with a latitude of about 5 minutes 
either way. Agitation should be thorough throughout the operation, 
and particularly at the start. Very often the orchardist does not 
fully appreciate the importance of accurately timing the boiling, and 
so produces an underboiled or overboiled concentrate. In either 
case, the amount of sediment is increased. Strict adherence to the 
proper boiling period is important if the best results are to be obtained 
and, as previously noted, care should also be taken not to allow the 
volume of the boiling mass to drop below that given for the finished 
product. 
Care required in making and handling.—During the cooking the 
mixture should be watched and any sulphur lumps or globules formed 
should be broken up by means of a paddle. When working over open 
kettles or vats, care should be taken to protect the eyes from the in- 
jurious fumes and sulphur particles that may pass off. For this pur- 
pose the operator may wear goggles. Lime-sulphur solution is also 
very caustic and injurious to the skin so that care should be exercised 
when handling it. The use of leather gloves well oiled or greased on 
the inside and outside is advised. If gloves are not worn it is well 
to protect the hands and wrists with an application of vaseline. 
STRAINING THE PRODUCT. 
As soon as the cooking has been completed the lime-sulphur con- 
centrate should be drawn off (see also page 24), strained, and run into 
a settling tank,if one is used, or directly into the storage receptacles. 
A strainer (brass or tinned iron, never copper) of 20 meshes to the 
inch will remove the coarser particles so that the material passing 
through will be satisfactory for spraying purposes. Very often, 
however, a still finer screen, 30 to 50 mesh, is used to remove the finer 
sediment, or, in some instances, the material is passed through two 
strainers, the first a 20-mesh to remove the coarser particles, and the 
second a 30 to 50 mesh. In some commercial and community plants 
the concentrate is run through a filter press which removes both the 
fine and coarse sediment. 
® Hot liquids contract on cooling, the rate of contraction of water being approximately 
4 per cent on cooling from the boiling point to 60° F. Thus it will be found that 50 
gallons of lime-sulphur concentrate at the close of the cooking will have a volume of 
about 48 gallons after it has cooled to 60° F. 
4To determine when the sulphur granules have gone into solution, dip out some of 
the material and slowly pour it from one container into another, observing whether or 
not the granules are present. 
