ELECTROCHEMISTRY—RICHARDS. Lie 
this city. At McKeesport tubes are coated on an immense scale, 
by dipping into melted zinc, but the electrolytic method is gaining a 
foothold, and we may live to see all galvanizing in reality practiced 
as it is spelled. The removing of metallic tin from waste tin scrap is 
also accomplished on a large scale by the application of similar prin- 
ciples. It is being operated at a distance from Pittsburgh, but your 
open-hearth furnaces use up annually thousands of tons of the scrap 
steel thus cleaned and saved for remanufacture into useful shape. 
Without having mentioned or described more than a fraction of the 
electrolytic methods in actual industrial use, I hope that I have made 
clear the importance and extent of this kind of electrochemical proc- 
esses. Assuming this, we will pass to the consideration of another 
entirely different and yet important class of apparatus and processes. 
Il. 
Electric arcs and high-tension discharges through gases are capable 
of producing some chemical compositions and decompositions which 
are very useful and profitable to operate. This is a branch of electro- 
chemistry which has not been as thoroughly studied as some others, 
its phenomena are not as thoroughly under control as electrolysis and 
electrothermal reactions, and its possibilities are not as thoroughly 
understood or utilized. 
Ozone is being made from air by the silent discharge of high-tension 
electric current. The apparatus is so far simplified as to be made in 
small units suitable for household use, ready to attach to a low-tension 
alternating current supply. The uses for the ozone thus produced 
are particularly for purifying water and air. It makes very impure 
water perfectly safe to drink and purifies the air of assembly halls 
and sick rooms, acting as an antiseptic. According to all appear- 
ances, this electrochemical doubling up of oxygen into a more efficient 
oxidizing form is developing into a simple and highly efficient aid to 
healthy living. 
Nitric acid is an expensive acid made from the natural alkaline 
nitrate salts, such as Chili saltpeter. These nitrates are the salvation 
of the agriculturist, for they furnish the ground with the necessary 
nitrogen which plants can assimilate. The Chili ‘‘nitrate kings”’ 
have gained many millions of dollars, even hundreds of millions, in 
thus supplying the world’s demand for fertilizer. But electro- 
chemistry has another solution to this problem, which is rapidly 
rendering every country which adopts it independent of the foreign 
fertilizer. The air we breathe contains uncombined nitrogen and 
oxygen gases, which, if combined and brought into contact with 
_ water, furnish the exact constituents of nitric acid. The way to do 
this has been laboriously worked out, and the electric are is the agent 
which does it. Air is simply blown into the electric arc, where it for 
