This section is from the book "Monograph on Flavoring Extracts With Essences, Syrups, and Colorings", by Joseph Harrop . Also available from Amazon: Monograph On Flavoring Extracts With Essences, Syrups And Colorings.
Take a glass tube, four or five inches long and one-fourth of an inch in diameter. Close one end by fusing in the flame of a spirit lamp; three-fourths of an inch from this end file a hole with a rat-tail file, moistened with oil of turpentine, in which a small quantity of camphor has been dissolved.
In the small end of funnel place a cork, through which a hole has been made, that will allow the tube to fit tightly. Insert the closed end of the tube in the cork so that the aperture in the side shall be just below the top of the cork. When the contents of the funnel are to be drawn off, push the tube into the funnel until the hole is just above the cork. When the heaviest liquid has passed out, pull the tube down until the hole is just below the cork; this allows the air to enter, and the liquid remaining in the tube to flow out; then by pushing the tube into the funnel as before, the remaining liquid can be drawn off.