The metallic state in general is characterized by the presence of innumerable freely moving negatively charged and extraordinarily minute particles called electrons. Their presence in any substance makes it appear metallic; the remarkable facility for conducting heat and electricity, which metals possess, depends upon these same electrons; and reflecting power and opacity are correlated with their activity. Ductility, malleability, strength, and welding power also may be attributed possibly to these persistent and mobile components.
Whenever a metallic substance is dissolved in an aqueous medium, the electrons characteristically are available for the production of an electric current, while the main atomic aggregate enters the liquid, now burdened with its residue of corresponding positive electricity. The greater the tendency thus to enter solution, the more electropositive a metal is, and the more pronounced are all its other metallic properties. No two elements agree exactly in their tendency to go into solution, and, as they spread over quite a range of electrical solution potential, just as their atomic weights are spread at intervals over a considerable range, we can arrange them in an electrochemical series. Elements which fail thus to enter solution bearing a positive charge lack all metallic attributes.
The systematic study of the science of metallurgy includes the following common divisions:
These divisions treat of certain more limited fields from the electrical and wet-chemical viewpoints, respectively. Individual metals, processes, or appliances, when important enough, are commonly treated as separate subjects; such are: the metallurgy of steel, foundry practice, and electric furnaces.
This is a strong young science which treats of the structure of the metals; it especially studies all the internal physical and chemical properties of the metallic state; it investigates metallic compounds, liquid and solid metallic solutions, solidifica-tions, transitions, and crystal form.
The art of metallurgy consists in extracting the metals from their ores and in purifying and preparing them for consumption in the manufacturing industries and trades. Of course quite a bit of ore preparation often is included in metallurgy; likewise much manufacturing may be tagged on to strictly metallurgical operations, as when a steel plant sends its product out in the shape of railroad spikes.
Metallurgy cannot confine itself to a study of the preparation and properties of the nineteen common metals - sodium, magnesium, aluminum, iron, nickel, copper, zinc, palladium, silver, cadmium, tin, antimony, tungsten, iridium, platinum, gold, mercury, lead, and bismuth - and of the seven common alloying elements - silicon, titanium, vanadium, chromium, manganese, cobalt, and molybdenum - but finds itself in the most intimate contact with, and use of, many of the other phases of human activity.
Mining engineering equally is concerned with the recovery of placer gold; the miner must dig for the metallurgist, just as the miner can afford to recover only those ores which the metallurgist can use. Ore dressing is claimed by mining engineering and by metallurgy, and is made independent only by a strong exponent. Chemical engineering in one school may embrace metallurgy, in another it may be separated fully. Electrical engineering finds a fertile field in metallurgical plants; civil and mechanical engineers often are at the same problem with the metallurgist, who as far as possible, must master their accomplishments.
The metallurgist often must do work in the strictest and purest fields of physics, chemistry, and mathematics; and their progress is the foundation for all his best efforts. Not seldom do political economy, finance, transportation, and hygiene modify his operations profoundly, but the metallurgist needs now and then to adjust his operations to the whims and traditions of those who work with him and those who buy his product.
The importance of metallurgy is evident when we consider that the essential features of our modern civilization are woven on a support of iron and steel; remove this metallic skeleton or imagine it lost, and our personal sphere utterly collapses.
Hardly an effort of labor can be performed without the use of a metallic object, be it the work of the laborer in the ditch with his iron-carbon alloy, or the President signing a state document with a platinum-iridium pointed gold pen. We live in homes well equipped and decorated with metallic objects; we carry metallic objects for use and show - the same as fabrics - and consider a gem perfect only in the most costly setting.
The transportation of ores is the greatest tonnage commodity of the railroads. The strictly metallurgical industries rank well to the front - as far as the money value of our yearly products is concerned, over a billion dollars' worth of metal in the unfabricated state being produced each year. The stock of accumulated metals is one of the chief treasures and resources of any people.
Gold is the standard of value and the basis of finance. While our national wealth, both private and public, is increasing enormously year by year, our gold production is not quite a dollar's worth per person at the present time. For over 100,000,000 people, the United States produced slightly under $99,000,000 in gold during 1915. As a matter of fact, the world's production of gold now is on the decline. Trade exigencies swing the transfer of gold violently from nation to nation. One year we export more than we mine; another, the whole world's production of some $450,000,000 is shipped to us. Financial panics are largely scrambles for gold. Gold has slight intrinsic value and any rational substitution of a new material for it or of a fiat basis for values, immediately would have the most profound and sweeping reaction, not only on gold mining, but on the entire number of industries connected with the production of silver, copper, and lead.
This year there is produced, per capita, in the United States over 800 pounds of iron, 13 pounds of copper, 10 pounds of lead, 8 pounds of zinc, and 1½ pounds of aluminum. We are, by far, the leading nation in the production and use of the metals. There are strong indications that more populous nations than our own gradually will find need for the metals, as we do. There is, therefore, little likelihood of any very long continued slump in either metal production or metal values.
Matters of the greatest import are the progress continually being made in the production of purer and purer metals in huge quantities, and the striking success in making alloys of new properties. There is no reason to think otherwise than that this phase of metallurgy is still in its beginning; a conception promising to everybody.
The bulletins of professional, scientific, and government bodies afford an abundance of first-class information on all current metallurgical subjects. The trade journals get some new articles, but mainly spread the more technical information of the first group. Perfunctory treatises demand such attainment by their authors that, if they are at all broad in scope, they fail lamentably. Treatises on special subjects, on the contrary, are usually very much worth while. In general, both the science and the industry are presented exceptionally well to the public.
The information contained in the following treatises and periodicals is of the first quality. General Metallurgy:
"Introduction to Metallurgy", Roberts. Austen (1910)
"Principles of Metallurgy", Fulton (1910)
"Metallurgical Calculations", Richards (1907)
"Physical Metallurgy". Rosenhain (1914)
"General Metallurgy", Hofman (1913)
"Metallographie", Guertler (1912-1913)
"Revue de Metallurgie" (monthly), Paris.
"Metallurgical and Chemical Engineering" (semimonthly), New York.
"Metall und Erz" (monthly), Halle.
"Bulletin, American Institute of Mining Engineers" (monthly), New York.
"The Mineral Industry" (yearly), New York Iron and Steel:
"Cast Iron in the Light of Recent Research", W. H. Hatfield (1912).
'The Metallurgy of Steel", Harbord and Hall (1911).
"Liquid Steel", D. Carnegie (1913).
"Metallography and Heat Treatment of Iron and Steel", Sauveur (1916).
"Metallography of Steel and Cast Iron", Howe (1916) "Cementation of Iron and Steel", Giolitti (1914) "Stahl and Eisen" (weekly), Duesseldorf 'The Iron Age" (weekly), New York 'The Iron Trade Review" (weekly), Cleveland Copper:
"Metallurgy of Copper", Hofman (1914) "Practice of Copper Smelting", Peters (1911) "Hydrometallurgy of Copper", Greenawalt (1912) Lead:
"The Metallurgy of Lead", Collins (1910) Zinc:
"Zink und Cadmium", Liebig (1913).