SIXTH ANNUAL YEAR BOOK — PART VIII. 909 



Where woven wire and barbed wire are combined in making the 

 fence, the woven wire should have metallic connection with the barbed 

 wire and with the ground, thus enabling a free passage for the develop- 

 ing current of electricity. 



Our readers may wish to know what we mean by negative and positive 

 electricity. They are simply terms which scientists have invented to 

 express two opposing forces. To illustrate further what we mean, if 

 any of our readers will put one of his boys on a piece of beeswax or a 

 piece of glass or a stool with glass on the legs and thrash him a few 

 times Avith a cat's skin, especially a black cat, he will find the boy so 

 fully charged with electricity that his hair will stand on end "like quiii 

 prickling porcupine." If now he will present to the boy an awl or som^ 

 other steel or iron instrument the electricity will be drawn out from him, 

 frequently without a spark, but if he will present to him a blunc yie^. 

 of iron say one inch in diameter, the electricity will still pass off, but 

 v/ith a very perceptible spark and shock. This explains why the light- 

 ning rods are sharp pointed and why the barbs on the wire act as light- 

 ning rods in protecting the farm, only, however, if they are properly 

 grounded in order to allow the developing negative electricity to pass 

 out into the air without violence. 



TREATMENT OF FENCE POSTS TO INCREASE DURABILITY. 



I:V II. P. BAKER, FOEESTER TO THE STATE EXPERIENCE STATION, AMES, IOWA. 



Even with the increased use of cement and steel there is an increas- 

 ing use for wood in all industries, but wherever wood is used to any 

 extent there is a tremendous amount of work and expense due to various 

 kinds of rotting. Four things are necessary for the natural decay of 

 timber, namely, water, air, heat and some fungous growth. If one of 

 these factors is absent, decay cannot take place, though many have be- 

 lieved m the past and many still believe that decay takes place without 

 the aid of fungi. It has, however, been proved beyond question that 

 spontaneous decay or oxidation of wood, cannot occur, hence if we can 

 prevent the presence of one of the above mentioned factors of decay, we 

 can preserve wood to be used for any purpose indefinitely. 



Noah was told to pitch the ark within and without and Pliny recom- 

 mended oil of linseed to preserve the statute of Minerva. In parts of 

 Egypt where rainfall is extremely small, wooden structures have stood 

 for centuries because of the dryness. The great Brooklyn bridge is built 

 upon wooden foundations which are below low-tide mark. Air cannoi, 

 reach these wooden foundations, hence there can be no decay. It has 

 been known for centuries that the charring of wood tends to preserve it. 

 and this old and simple method can still be used to great advantage 

 when more effective methods of treatment cannot be given. 



By far the cheapest and at the same time a sure method of wood 

 preservation is thorough seasoning. It is a common fact that if a post 

 or pole be cut at the right time of the year, peeled and thoroughly sea- 

 soned that it will out-last, often by years, a post of the same species is 



