** How to Make Blueprint Lantern Slides [120]

Lantern slides of a blue tone that is a pleasing variety from the usual black may be made from spoiled or old plates which have not been developed, by fixing, washing well and then dipping five minutes in the following solution: 

A. Green Iron ammonium citrate    150 gr. 
Water                            1 oz.

B. Potassium ferrocyanide          50 gr. 
Water                            1 oz.

Prepare the solutions separately and mix equal parts for use, at the time of employment.  Dry the plates in the dark, and keep in the dark until used.  Printing is done in the sun, and a vigorous negative must be used, says the Moving Picture World.  Exposure, 20 to 30 minutes.  Wash 10 minutes in running water and dry.  Brown or purple tones may be had by sensitizing with the following solution instead of the above: 

    Distilled water 1 oz. 
    Sliver nitrate 50 gr. 
    Tartaric or citric acid 1/2 oz.

Bathe the plates 5 minutes, keeping the fingers out of the solution, to avoid blackened skin.  Dry in the dark.  Print to bronzing under a strong negative; fix in hypo, toning first if desired.

** A Substitute for a Ray Filter [120]

Not many amateur photographers possess a ray filter.  A good substitute is to use the orange glass from the ruby lamp.  This can be held in position in front of the lens with a rubber band.  A longer exposure will be necessary, but good cloud effects can be procured in this manner.

** Electric Lamp Experiments [120]

Incandescent electric lamps can be made to glow so that they may be seen in a dark room by rubbing the globe on clothing or with a paper, leather or tinfoil and immediately holding near a 1/2-in.  Ruhmkorff coil which is in action but not sparking.  The miniature 16 cp., 20 and 22-volt lamps will show quite brilliantly, but the 110-volt globes will not glow.  When experimenting with these globes everything should be dry.  A cold, dry atmosphere will give best results.

* * * * * * *

[Illustration:  Annual Regatta, Port Melbourne, Australia]

** How to Make a Simple Wireless Telegraph [121] By Arthur E. Joerin

An efficient wireless-telegraph receiving apparatus for distances up to 1,000 ft. may be constructed in the following manner:  Attach a watchcase telephone receiver to a dry cell, or battery, of any make.  The negative pole, or zinc, of the cell is connected to a ground wire.  This is done by attaching to a gas or water pipe.  The positive pole, or carbon, of the cell is connected to the aerial line.  This aerial collector can be made in various ways, either by using a screen wire or numerous wires

[Illustration:  For Distances up to 1000 Feet]

made in an open coil and hung in the air.  File a V-shaped groove in the upper end of the carbon of the cell.  Attach a small bent copper wire in the binding post that is attached to the zinc of the cell.  In the bend of this wire and the V-shaped groove filed into the carbon, lay a needle.  This will complete the receiving station.  Use a spark coil in connection with a telegraph key for the sending station, making a ground with one wire, and have the other connected with another aerial line.