The illustrations show two methods of securing papers or photographs in a mailing tube. In Fig. 1 the mailing tube A is shown in cross section and the manner of running the string through the pasteboard walls illustrated. The ends of the string are drawn up and tied over or under the label. If the label is pasted over the string or string ends as they are tied, it makes a sealed package which is rated as first-class matter.
The String in Either Case Prevents the Papers from Slipping Out of the Mailing Tube (Fig. 1)
The second way is to run the cords in a cross form through holes near the ends, as in Fig. 2, then tie the knots as at BB. In each instance even if the papers fit the tube loosely, they will be held securely and can be easily extracted when the knots are untied.
(Fig. 2)
Cooling Tube for a Laboratory Still
A simple and very effective device to replace the cumbersome cooling or condensation coil of a still for the amateur's laboratory can be easily made as follows:
Procure an ordinary straight glass tube of fairly large diameter and heat it in the flame of an alcohol lamp with the use of a blowpipe or in a Bunsen burner with a very reduced flame so that only a small spot of the tube is brought to a red heat at one time Then, with a previously pointed and charred stick of wood—a penholder for instance—produce a small recess in the wall by pushing the charred end gently into the glowing part of the tube. This procedure is repeated until the whole tube is thus provided with small recesses. The indentations should be made in spiral lines around the tube, thus increasing the surface that is in contact with the cooling water. The operation of making the recesses is shown in Fig. 1. The walls of the recesses should have a regular and uniform slant.
