lime and salt with oil, or white lead with gasoline. There are 
several products on the market for cleaning glass. 
In the home the maximum amount of light can be obtained from 
south windows, and Cattleyas will grow well in this situation. 
In most areas, shading is necessary in summer. An adjustable 
shading system is the best way of getting the desired light inten- 
sity. Some of the materials that maybe used are Venetian blinds, 
roller lath shades on runners a foot above the glass, or cheese- 
cloth with eyelets so that it may be drawnover the plants on bright 
days and pulled back on cloudy days. 
Shading compounds as white lead and gasoline may be sprayed on 
the glass. However, this compound is difficult to remove. We 
recommend our special Rivermont shading compound. 
REGULATING THE TEMPERATURE. Heating and ventilationare 
the most important methods of keeping the temperature within the 
desiredlimits. Oil, naturalgas, or electricity are popular sources 
of fuel. The most economical heating can be obtained by the use 
of hot water. 
Thermostatic controls in both heating and ventilation can be very 
practical. Their use has helped the grower who has to be away 
during most of the day. On bright days, direct solar heat and 
radiation cause the temperature to rise in the house. The heat 
should, therefore, be turned off or the ventilators opened. In 
winter, care should be taken to prevent cold air from rushing in. 
Ventilators should be opened on the leeward side. 
Potting 
A Cattleya plant needs repotting when: (1) it has outgrownits pot; 
(2) the osmundine has decayed to a point where it starts to fall 
apart (indicated by its readily breaking off when a pinch is taken 
between the fingers.) These two conditions are ordinarily reached 
after two years. When a plant has to be repotted, it is best to 
wait until one or two roots start to develop from the base of the 
lead. 
Select a pot large enough to permit growth of two successive 
