A paste for the positive plate is made from 1 part sulphuric acid and 1 part water with a sufficient amount of red lead added to make of thick dry consistency.  When mixing the acid and water, be sure to add the acid to the water and not the water to the acid.  Also remember that sulphuric acid will destroy anything that it comes in contact with and will make a painful burn if it touches the hands.  Stir the mixture with a stick and when a good dry paste is formed, put it into the smaller tube and ram it down until the tube is almost filled.  The paste that may have come through the holes is scraped off and the tube set aside to dry.  The large tube or cup is filled with a diluted solution of sulphuric acid.  This solution should be about one-twelfth acid.  The cell is now complete and ready for storing the current.

The cell may be charged with three gravity cells.  These are connected in series and the positive terminal binding-post on the storage cell is connected to the wire leading from the copper plate in the gravity cell.  The other plate is connected to the zinc.  The first charge should be run into the cell for about one week and all subsequent charges should only take from 10 to 12 hours.

** Fitting a Plug in Different Shaped Holes [122]

A certain king offered to give the prince his liberty if he could whittle a plug that would fit four different shaped holes, namely:  a square hole, a round one, an oblong one and a triangular one, says the Pathfinder.  A broomstick was used to make the plug and it was whittled in the shape shown

[Illustration:  Fits Four Different Shaped Holes]

in Fig. 1.  The holes in the different places as shown in Fig. 2, were fitted by this one plug.

** How to Make a Lightning Arrester [122]

Secure a piece of wood about 3-1/2 in. square that will furnish a nice finish and round the corners and make a small rounding edge as shown in the sketch.  From a piece of brass 1/16 in. thick cut two pieces alike, A and B, and match them together, leaving about 1/16 in. between their upper edges and fasten them to the wood with binding-posts.  The third piece of brass, C, is fitted

[Illustration:  Lightning Arrester]

between the pieces A and B allowing a space of 1/16-in. all around the edge.  One binding-post and a small screw will hold the piece of brass, C, in place on the wood.  The connections are made from the line wires to the two upper binding-posts and parallel from the lower binding-posts to the instrument.  The third binding-post on C is connected to the ground wire.  Any heavy charge from lightning will jump the saw teeth part of the brass and is grounded without doing harm to the instruments used. —­Contributed by Edwin Walker, Chicago, Ill.

** A Home-Made Punt [123]

A flat bottom boat is easy to make and is one of the safest boats, as it is not readily overturned.  It has the advantage of being rowed from either end, and has plenty of good seating capacity.