When an excess of oil has been employed, or the operation of cutting the oil is not properly conducted, particles of oil will separate, rise and appear on the surface of the essence. Some oils separate most invariably part of the oil again, and cover sometimes even the whole surface. Fig. 420 illustrates the operation with a pipette when taking off the undissolved and separated oil from the top; even small particles of oil may thus be saved and afterwards dropped in a separate bottle for another operation. The other illustration, Fig. 421, represents a separa-tory funnel with support, also a convenient contrivance for regaining the separated oil. Close the cock and pour all, or as much as it will hold of the liquid, into the funnel, allow it to rest and separate for a few seconds, when the oil will rise to the top. Then open the cock slightly, let the essence run into a bottle, then stop the cock, place another bottle beneath and run in the oil separately. By these methods many a small quantity of oil may be advantageously saved that otherwise would be lost - left on the filter and the latter thrown away.

Fig. 420.   Pipette

Fig. 420. - Pipette.

Fig. 421.   Separatory Funnel

Fig. 421. - Separatory Funnel.