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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G . C H E M I S T R Y
EDITORIALS
NITRATES IN COLORADO SOILS I n a number of publications, Headden, of the Colorado Experiment Station, has shown t h a t t h e soils of Colorado contain in various places excessive quantities of nitrates. Ordinarily good, cultivated soil he found t o contain from 5 t o 8 parts of nitrates per million of t h e dry soil. I n the nitrate areas, however, many thousand p a r t s per million of nitrate nitrogen were found. I n one sample of surface soil there were found 6.54 per cent of sodium nitrate or nearly 11 tons in a n acre of ground taken t o t h e depth of I inch. The high nitrate content is generally found in spots b u t these spots often grow t o cover large areas. T h u s what was five or six years ago a spot has grown t o involve as much as six, eight, and more acres. T h e nitrates are present in large quantities in numerous areas scattered over goa t o 400 square miles. The orchards in a single district including j o square miles have been practically ruined. These observations a n d studies are of so great interest a n d importance t o agricultural investigators t h a t it is a matter for congratulation t h a t Professor Headden has been prevailed upon t o furnish his own statement of his work in other columns of THIS J O U R N A L . A brief repetition of t h e principal results, however, c a n be given here. As a result of t h e nitrate accumulation, in a number of places large areas have been made sterile. Whether large or small t h e affected areas are characterized b y a brown coloration, mealiness of t h e soil, a high nitrate content, and, unless the nitrate content is excessively high, b y t h e presence of nitrogen-fixing organisms such a s azotobacter. With t h e increase in t h e colored patches a n d t h e amount of nitrate, t h e crops covering t h e involved areas rapidly deteriorate and even die out. T h e greatest injury has been t o t h e apple orchards though other crops such as alfalfa, sugar beets, etc., have been seriously injured. T h e trouble is common t o several sections of t h e State. Sometimes i t has occurred in light sandy loams, sometimes in clay soil, sometimes in comparatively low-lying lands, again on hillsides. Sodium chloride is also present in large amounts in t h e Colorado soils. According t o Headden, however, this salt though injurious in large amounts does not produce a n y of t h e characteristic phenomena observed in t h e dying orchards, while application of large quantities (j pounds t o a four-year-old tree) of sodium nitrate t o a n experimental orchard and irrigating t o bring t h e nitrate in contact with t h e feeding roots reproduced t h e identical phenomena noticed in t h e other orchards where t h e trees had died. It would seem then t h a t whatever contributing cause there may be, t h e sodium nitrate present in t h e soil is sufficient t o bring about t h e deterioration and death of trees and crops in t h e affected areas. Though t h e presence of t h e highly excessive quantities of nitrate which bring about loss of general productivkness involves only a small percentage of the arable Colorado soil, t h e formation of these high nitrate areas
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i n t h e various sections of t h e State is a problem of great importance a n d concern t o agriculturalists of Colorado a n d a phenomenon of t h e greatest interest t o chemists and bacteriologists. I n soils in general t h e formation of nitrates is brought about b y several soil microorganisms which fix nitrogen from t h e air, form ammonia from more complex nitrogenous compounds, a n d form nitrites a n d nitrates from ammonium compounds. As a rule t h e nitrates in soil are small in amount. Accordingly, t h e Colorado situation is exceedingly remarkable. As t o t h e origin of t h e nitrates there is some dispute. Headden holds t h a t t h e abnormal accumulation of nitrates cannot be due t o evaporation of surface waters containing nitrates coming from a distance from soil or shale since: ( I ) neither soil nor shale contain a supply of nitrogen adequate t o account for the formation of nitrates found; ( 2 ) t h e natural water a n d t h e irrigation water contain only small quantities of nitrates; (3) t h e brown nitrate-containing areas often occur a t a high elevation. I n addition t h e accumulation of nitrates may occur on well drained lands, where t h e water level is some distance from t h e surface. Headden's positive conclusion is t h a t t h e source of t h e nitrates is t h e atmosphere, t h e nitrogen of which is fixed by azotobacter. I n support of Headden's conclusions, Sackett found t h a t t h e Colorado soils were rich in azotobacter which had t h e power t o fix nitrogen in solution a n d in soil a n d fixed i t a t a rate sufficient t o account for the nitrates found in t h e soil, provided t h e nitrogen is nitrified by other organisms. Sackett likewise found t h a t the Colorado soils have a higher ammonifying power t h a n have ordinary soils a n d a higher nitrifying power a n d comes t o t h e conclusion t h a t t h e excessive nitrate present in certain Colorado soils has resulted from the combined action of nitrogen-fixing, ammonifying, a n d nitrifying organisms. Since t h e Colorado soils are poor in organic matter a n d azotobacter requires a supply of carbohydrate for its development a n d t h e fixation of nitrogen, it seemed difficult t o account for t h e source of energy necessary t o support such a rich nitrogen-fixing flora as possessed by t h e soils in question. Robbins, however, found t h e algae flora especially t h e blue-green algae ( C y a n o p h y c e a e ) t o be very abundant. I t is well known t h a t certain bacteria a n d algae enter into symbiotic relationship in which t h e algae furnish t h e bacteria with a suitable form of carbohydrates. The algae in' t h e Colorado soil may furnish t h e necessary food material for azotobacter. An opposing view is t h a t of Stewart a n d Greaves (Agric. Expt. Sta., Utqh, BuIZ. 114) t h a t the nitrates of t h e Colorado soil have their origin in t h e country rocks. The fact t h a t in widely distributed areas in t h e arid west deposits of nitrates are found which do owe their origin t o leaching from t h e country rock, supports, in their opinion, t h e theory t h a t t h e excessive quantities of nitrates found in the soil of Colorado owe thcir origin
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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
t o t h e same source as d o t h e other water-soluble salts. Further, Stewart a n d Greaves claim t h a t in Headden’s work wherever there was a variation in nitric nitrogen there was a variation in chlorine in t h e same direction which would seem t o indicate a common origin of t h e nitrates a n d chlorides. T o t a k e a particular case, they point out t h a t where there was a n increaese in t h e surface soil of j61 pounds of nitrates per acre two inches of soil during t h e years from 1909-1911 there was a n increase of 10,430 pounds or over five tons of chlorine. I n another case, referred t o by Headden in Bulletin 155, t h e nitrate nitrogen increased from 1907 t o 1911 from a trace t o 621 pounds. I n t h e same interval t h e chlorine content increased 236,883 pounds. They come t o the inevitable conclusion t h a t there must be a n upward movement of t h e water-soluble salts, t h a t t h e chlorides must come from t h e ground water. Accordingly, t h e y ask t h e pertinent question, “ W h y may not t h e nitric nitrogen be accounted for in t h e same way?” Evaporation of t h e soil water would explain t h e deposit of nitrates since according t o their calculations, assuming t h e optimum amount of water, 18 per cent, t o be present, only one-half year of maxim u m evaporation would deposit t h e quantity of nitrogen actually deposited in two years. If t h e ground water contains only 74.48 parts per million of chlorine as computed b y Headden, t h e evaporation would account for only 203 pounds of chlorine, whereas t h e actual amount found in t h e samples mentioned was
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m a n y times greater. So they conclude t h a t t h e ground water has a greater concentration in chlorine a n d nitrogen t h a n assumed a n d t h a t both accumulate in t h e surface soil by evaporation of t h e water. Stewart a n d Greaves do not deny t h a t nitrogen fixation m a y take place to a certain extent in the Colorado soil a n d in some places t o a n appreciable degree, b u t do hold t h a t whatever theory accounts for t h e accumulation of chlorides in t h e Colorado soils must account also for t h e greater portion of t h e nitrates present. T o these arguments of Stewart and Greaves, Headden has opposed numerous objections which cannot be considered here. Suffice i t t o say, t h a t while there can be no possible question of t h e occasional occurrence of abnormal quantities of nitrates in t h e “alkali” soils of Colorado, t h e origin of these excessive nitrate accumulations is not settled. I n their endeavor t o explain t h e origin of the nitrate a n d t o remedy t h e conditions as t h e y arise, t h e various investigators should meet with general encouragement. I t is greatly t o be desired t h a t t h e nitrate formation should be considered from all viewpoints t o t h e end t h a t accumulating d a t a a n d suggestions may t h e more quickly develop a n harmonious conclusion, t o t h e advantage of practical agriculture a n d t o t h e increase of t h e sum total of human knowledge. h l . X . SULLIVAN BUREAUO F SOILS DEPARTMENTOF AGRICULTURE WASHINGTON
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ORIGINAL PAPERS ELECTRIC FURNACES FOR HEATING STEEL’ B y ALCANHIRSCH Received M a y 25, 1914
T h e field of usefulness of t h e electric furnace for metallurgical purposes is so extensive t h a t i t is deemed advisable t o limit t h e scope of this paper t o a discussion of electric furnaces used for heating steel for t h e various kinds of heat treatment, forging a n d enameling. A broad view of t h e development of electric furnaces b y t h e writer a n d his associates during t h e past year, together with details of design, construction a n d operation, as determined b y t h e m are presented herein. T h e essential d a t a only are given as i t is believed t h a t extensive details are likely t o lead t o confusion. I t is thought such a presentation of basic principles will make t h e paper of more value t o users of electric furnaces t h a n an extended report of all t h e d a t a collected. Prior t o 1913 a t t e m p t s were made t o p u t forth furnaces for metallurgical purposes, b u t except for t h e very small furnaces, these cannot be considered as having h a d commercial success. T h e facts which form t h e basis of this paper occurred under t h e writer’s observation a n d are practically exclusively gathered from his experience of t h e past year. By reason of industrial practice a n d certain other 1 Author’s abstract of report on research carried out under a Carnegie Fellowship granted by the Iron and Steel Institute of Great Britain. The complete report of this work was presented a t the Annual Meeting of the Institute, M a y 7 , 1914.
limitations, both fuel a n d electric furnaces’ can be divided into two classes: I-Furnaces operating above 1800’ F. Forge furnaces are t h e main a n d most important division of this class. 11-Furnaces operating below 1800’ F. This class comprises furnaces for practically all heat treating as well as enameling. Although furnaces operating a t t h e lower temperatures will be considered first i t must be borne in mind t h a t t h e greater p a r t of t h e principle a n d theory underlying t h e construction and operation of moderate a n d low temperature furnaces also applies to t h e higher temperature furnaces. TRANSFEREKCE
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PROM
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The metal resting on t h e hearth of t h e furnace receives its heat in several different ways: ( I ) From t h e brickwork in t h e furnace in contact with t h e metal; (2) by conduction from t h e products of combustion; (3) b y radiation from t h e hot walls, roof a n d incandescent particles in t h e burning gases. Generally speaking, in t h e fuel-fired furnaces, each of these paths delivers heat of t h e same order of magnitude, b u t usually t h e amount of heat passing by means of brick a n d metal in contact is less t h a n t h a t by a n y other p a t h . If only a small portion of t h e heat passes into t h e m t t a l b y direct contact with t h e brick, t h e rate of heating in all except thin pieces is quite slow^. LIore frequcntly t h a n is generally supposed this p a t h of heat trans-
