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.
Castor oil is good to treat styes (oil gland infections found on the eyelid), apply a small drop with a fingertip 2-3 times a day. Castor oil is a natural emollient and stimulates production of collagen and elastin, which hydrates the skin making it appear smoother and softer. Great when used for wrinkles and age spots. The high vitamin E content in castor oil is excellent for brittle nails and ragged cuticles.