A potometer measures how factors such as light, temperature, humidity, light intensity and wind will affect the rate of transpiration. The main type of potometer is the 'bubble' potometer shown in Figure Figure 6.
Physicians recommended against the practice because they did not want medicines associated with punishment. A heavy dose of castor oil could be used as a humiliating punishment for adults, especially political dissenters. Colonial officials used it in the British Raj (India) to deal with recalcitrant servants. Belgian military officials prescribed heavy doses of castor oil in Belgian Congo as a punishment for being too sick to work.
Jamaican Black Castor Oil: More Potent. Jamaican black castor oil is said to be one of the most potent mixtures of castor oil. Because of the way it is processed, this type of castor oil produces the best effects. Jamaican castor oil started centuries ago when the castor beans were brought to Jamaica via the African trade.