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Jan 1, 1933

By O. J. Huber, P. D. Frost, H. A. Robinson

URANIUM is a (ß-stabilizing, eutectoid-forming element when alloyed with titanium. Udy and Boulger1 have reported that an alloy of 48.6 pet uranium in titanium retains ß-phase when quenched from the ß-region, while compositions of approximately 30 pet uranium transform to martensite during such quenching. Since the eutectoid reaction is rather sluggish, titanium-uranium alloys should be capable of being strengthened by the ß — a trans-

Jan 1, 1959

By Lo-Ching Chang, J. Chipman

C. B. POST*—Just what are you showing that has not been shown by fixing the attention on molecular species and choosing the molecular species to give you a perfect solution? J. CHIPMAN (authors' reply)—In general a fairly satisfactory thermody-uamic treatment of slag-metal equilibria can be worked out on the basis of assumed molecular species in the slag. This has been the method used by Shenck and more recently by White. Winkler and I also used it in studying dephosphoriza-tion. Darken and Gurry found that it did not fit satisfactorily in the case of their data on iron oxides. The ionic formulas used here conform to the data much better and probably correspond somewhat more closely with the actual structure of the slags. C. B. POST—It does seem to be similar to you? J. CHIPMAN—It is alternative, and may lead to a more complete understanding. C. B. POST—Have you had a chance to talk to glass technologists on this? Have they been using this type of set-up for glass solutions? J. CHIPMAN—Yes, and the ionic formulas have given them a little better understanding of what liquid glass is like. C. B. POST—Nelson Taylor always said we were going- about slag reactions from the wrong viewpoint when using molecular species. Evidently the glass technologists use ionic species exclusively when dealing with liquid glass reactions. J. CHIPMAN—I agree that it seems more rational and more accurate to use ionic rather than molecular formulas. We should be cautious, however, and not suppose that we really understand the structure of a slag just because we are able to fit its reactions by ionic equations.

Jan 1, 1950

The following table summarizes the information on the Hurghada field. which is still the major producing field in Egypt. Age of field to end of 1937. years..................... 24 Producing area for gas and oil. acres.................. 1.050 Babbels Total oil production to end of 1937................... 30.188.500 Total oil production during 1936..................... 1.219.406 Total oil production during 1937..................... 1.141.230 Average oil production per acre to end of 1937.......... 28.750 Average oil production per acre-foot to end of 1937.... 2.359 Daily average production (Nov. 1937)................ 3.162 Daily average production per well (Nov. 1937)........ 41.88 MillionB Cu. Ft. Total gas production (Aug. 1925 to end of 1937)....... 4,189 Total gas production during 1936.................... 281 Total gas production during 1937.................... 222.5 Maximum daily average in 1937 (July)............... 0.7 Number of producing wells completed to end of 1937... 97 Number of producing wells completed during 1937..... 3 Number of wells abandoned during 1937.............. 1 Producing wells at end of 1937....................... 78= Total number abandoned wella at end of 1937......... 19 Total number dry wells at end of 1937................ 20 Average depth of bottom of producing horizon, ft...... 1,720 Average depth of top of producing horizon, ft.......... 1,598 Character of oil, approximate average in 1937: gravity at 60" F., 0.900; base, mixed. Character of gas, approximate average during 1937: gallons gasoline per 1,000 cu. ft., 6.9. Producing rock (main): Nubian (?) sandstone. Cretaceous (?); character, sand rock and sandstone. 1 Figures were given in E. tons. A conversion factor of 6.98, based on 0.900 sp. gr., was used to obtain the number of barrels.—Ed. *All pumping.

Jan 1, 1938

W. P. WHITE,* Washington, D. C. (written discussion?).-The authors seem to have proved that for a phenomenon as irregular as the one they were investigating there was no perceptible conduction effect in the platinum wire. It should be mentioned, however, that the conduction of heat to and from small wires is not proportional to their surface and might give unexpected value, varying largely with the medium in which the wire was situated. Attempts to eliminate a conduction effect in the wire by extrapolating the curve obtained by using different sizes have in some cases given incorrect results, so that the authors' result should be applied with great care as a guide in other cases. The difference in size of wire employed by them is really rather small. If the desire had been to find out how great the effect was instead of merely to demonstrate its absence, a greater difference of diameter would, of course, have been selected. The sharp gradient immediately in front of the burning portion of the cigar is quite surprising at first sight. The weight of air coming from a flame is considerably greater than the weight of material burned, and it would be thought that this stream of heated air would heat very con-siderably the material not yet reached by the zone of combustion. Pos-sibly the heat is exhausted in evaporating moisture from the material. In that case the cigar is really a sort of regenerative furnace, except that it is not air but the, material which is preheated, and the pre-heating produces dryness rather than increase of temperature. Whether or not this is the case would be shown by finding how hot a thoroughly dry cigar would get.

Jan 12, 1919

By Frank C. Greene

The principal event in the development of oil and gas in Missouri in 1942 was the drilling of the Cities Service Oil Company's No. I Jim Cook, in the northwest corner, NW. 1/4 sec. 32, T. 65 N., R. 39 W., Atchison County, in the northwest corner of Missouri. This well, not yet completed, bailed several barrels of free oil in about 27° Baume from a sand called the Bartlesville by those in charge, at a depth of 1450 ft. The well is on a block of leases obtained after the area, which is covered by several hundred feet of glacial drift, had been prospected by core drilling. Earlier in the year the same company drilled a well on the Glen Gray farm in the southwest corner, SW. 1/4 sec. 29, T. 65 N., R. 39 w., to a depth of 2427 ft. in the Hunton lime with a rotary drill. Oil stains in this hole led to the drilling of the second well. Table i .—-Wells Drilled for Oil and Gas in Missouri in 1942 Country Number of Number of County Oil Wells Gas Wells Dry Andrew.......... Atchison.......... I Bates............ 2 6 Caldwell.......... I 3 Cass............. I Clinton........... I Holt............. I Jackson.......... I I Knox............ I Nodaway......... I Platte............ 4 4 Ray.............. 5 Sullivan.......... I Totals.......... I 7 28 Otherwise drilling in Missouri was uneventful, with a total of only 36 Completions, of which one was a very small oil well, Seven were small gas wells and 28 were dry holes. The total footage drilled was 24,7541/2 ft., of which 14,0281/2 was by cable tools and 10,726 ft. by rotary. Twelve of the dry holes were drilled into Mississip-pian or older beds. Table I gives a summary of activities by counties.

Jan 1, 1943

By R. W. Brauchli

The author has made a statistical analysis of the relations between recovery and length of cores, diameters of cores and of drill pipe, and cost of coring under different contractual conditions. The data are presented in tabular form. The length of the core appears to play a minor part in the percentage recovered, with a tendency to lower percentages with increased core length; approximately 50 per cent of the length cored is normally recovered if the cores are more than 2 in. in diameter. The diarneter of the core has a more pronounced influence on the recovery; 1 3/8-in. cores average 29.1 per cent, 2 1/8 -in. core 53.4 per cent and 3 1/8-in. cores with 6 5/8-in. drill pipe 68.5 per cent. Where 31/8-in cores were taken with smaller diameter drill pipe, i. e., 4 1/2 - in. drill pipe in 8 1/4-in. hole, the recovery dropped to 49.8 per cent, indicating that the more rigid drill pipe favors good core recovery, a conclusion also borne out by the results obtained in using large drill pipe for smaller diame-ter cores. Surprisingly good recoveries were obtained from both the Johnson and Simpson sands; shale, limestone and dolomite each gave less then average recoveries. No serious fishing jobs resulted from coring operations. Attention is called to the need of a core drill which will make it possible to drill a full-sized hole while coring, and thus reduce the cost of cores. Data pertaining to core drilling should be consistently recorded, such as, diameter of drill pipe and collar, diameter of core, recovery, size of cutter heads, type of core-barrel, coring time, speeds of rotation and of pumps, weight on core-barrel, etc.

Jan 1, 1933

By F. P. Dewey

(Read at Amenia Meeting, October, 1877.) AT the Wilkes-Barre Meeting of the Institute, Dr. J. Lawrence Smith, in the course of his remarks on some peculiarities in the composition of irons, alluded to the so-called " buckshot" iron, and exhibited a specimen of this material. He said that when the small granules, or shot, were separated from the mass, they could be flattened under the hammer, and inferred that these particles had been decarburized by the blast before sinking into the hearth of the furnace, and thus we had the exceptional production of wrought iron in the blast furnace. I have recently obtained a characteristic specimen of this variety of iron from one of the furnaces at Orbisona, Pa. Considerable uncertainty existed as to its true nature and the conditions of its production. Its weight seemed to preclude the idea that it contained much or any slag, yet its lack of strength indicated that it was not homogeneous cast iron. At times considerable quantities had been produced, which could only be utilized by charging in the furnace and remelting. The specimen, on the freshly fractured surface, appeared to consist of flattened globules of iron cemented together by a bluish material which one would naturally suppose to be slag, and qualitative examination for lime strengthened this supposition. It was quite difficult to obtain drillings, as there was a tendency to split in several directions as soon as pressure was applied ; but enough was obtained to undertake quantitative determinations. They were found to consist of two portions-one attracted by the magnet, and the other not. By repeated separation the magnetic portion was found to be 94.44 per cent., and the non-magnetic 5.56 per cent. Analyses of these gave the following results :

Jan 1, 1878

By Charles C. Hall

The following procedure in estimating mineral oil when mixed with vegetable or animal oils, is the result of a long series of cxperiments based on the method suggested by Sir William Thompson and Mr. A. H. Allen, in a paper read before the Royal Society.* Four to five grams of the oil under examination are weighed out into a porcelain capsule of 75 C.C. capacity. Thirty C.C. of a 10 per cent. solution of potassium-hydrate in alcohol are added, and the capsule covered with a watch-glass is placed in a water-bath heated to about 93' C. The mixture of oil and alkali should be stirred frequently, and after three-quarters of an hour it is boiled with stirring. This will secure the complete saponification of all the vegetable or animal oil. After the boiling has been continued some time, and most of the alcohol is expelled and a thick scum of soap forms on the surface, a little bicarbonate of soda is added to convert the excess of caustic alkali into carbonate. When the contents of the capsule have become pasty an equal bulk of fine, clean sand is stirred in. This makes the soap granular, and facilitates the removal of the last traces of alcohol. The capsule is now heated for two hours more on the water-bath. After cooling, the contents of the capsule are transferred to a short-necked funnel, having a thin plug of asbestos, and washed with petroleum-ether, or some other light petroleum spirit. The ether dissolves out the mineral oil from the soap, and is best collected in a quarter-liter flask having a short neck. The ether can be applied conveniently and effectively by a small washbottle. Care must be taken to effect a complete removal of the oil

Jan 1, 1883

By R. W. Dr. Raymond

(Read at the Philadelphia Meeting, February, 1878.) THE manufacture of ferromanganese in the blast furnace having been the subject of considerable attention in the Institute, I beg to put on record a contribution to the discussion from a quarter hitherto not directly represented, namely, the St. Louis furnaces, near Marseilles in France, belonging to a company of which M. Jordan, a member of the Institute, is Managing Director. These furnaces commenced in 1862 to manufacture specular pig (fontes à facettes) containing from three to six per cent. of manganese. In 1864 the regular production of spiegeleisen (fontes miroitantes), containing seven to ten per cent, of manganese, was inaugurated. At that time the Rhine was the only locality of this manufacture, and the Bessemer works of England and France obtained from Germany all their spiegel. From 1864 to the present time, the St. Louis furnaces have been advancing steadily the percentage of manganese in their product. From ferromanganese of thirty per cent. they had arrived, about two years ago, at a product containing seventy to seventy-five per cent., and for some time past they have been turning out what, as M. Jordan remarks, may fairly be termed fonte de manganese, or manganese pig, instead of iron, since the percentage of iron it contains is not more than 8.5, while the percentage of manganese is 85, or ten times as great. This very high grade material has a peculiar appearance, entirely different from that of ordinary cast iron or spiegel. It is granular, and steely gray in color. The following analyses, communicated to the Société to des Ingenieurs Oivils, by M. Jordan, show the composition of various products of the St. Louis furnaces :

Jan 1, 1878

By W. E. C. Coxe

AT the meeting of the Institute in Philadelphia, in June, 1876, it was my pleasure to read a paper on the "Manufacture and Endurance of Iron Rails." I then spoke of some trial rails which had been placed in the down track of the Philadelphia and Reading Railroad, over which passed, in addition to merchandise and passengers, most of the heavy coal traffic of that company. One of these rails, made at the Philadelphia and Reading Rolling Mill in 1870, and then placed in the track, was removed in 1876, after having carried about 55,000,000 gross tons, and was on exhibition at the Centennial Exhibition. A piece of this worn rail, twisted cold, was also shown there. One of the same series of rails was allowed to remain in the track until 1878, and short sections of this rail, as well as one not worn, to show its original shape, are presented for your inspection. A comparison of the two will show that the top of the head or tread has worn down 3/16 ths of an inch during its nine years of service. It carried in that time 67,000,000 gross tons of freight, passengers, cars, and engines. This rail was made in the usual way of manufacturing iron rails at the Philadelphia and Reading Rolling Mill. The head was made from puddled iron bars, piled, heated, and rolled into bars, 4 1/2 and 3 inches wide by 1 inch thick, these bars, breaking joints, were made into a pile in section 9 inches square, heated and rolled into slabs 9 inches wide and 2 inches thick; the balance of the rail-pile was made of 4 1/2 and 3-inch bars, rolled from two-thirds old rails and one-third puddled iron, the

Jan 1, 1880

Statistics compiled by the United States Geological Survey show that the iron ore mined in the United States in 1917 reached a total of 75,288,851 gross tons, exceeding the former record output of 1916 by 121,179 tons. The shipments from the mines in 1917 were 75, 573,181 gross tons, valued at $238,260,333, a decrease in quantity of 2,297,372 tons, or 2.95 per cent., and an increase in value of $56,358,056, or 30.98 per cent., over the shipments in 1916. The average value per ton at the mines for all grades of ore in 1917 was $3.15 as against $2.34 in 1916. Stocks of iron ore at mines, mainly in Minnesota and Michigan, amounted at the close of 1917 to 10,628,908 gross tons, compared with 10,876,352 gross tons in 1916. The quantity of pig iron, exclusive of ferro-alloys, sold or used in 1917, according to reports of producers to the United States Geological Survey, amounted to 38,612,546 gross tons, valued at $1,053,785,975; compared with 39,126,324 gross tons, valued at $663,478,118 in 1916, a decrease of 1.32 per cent. in quantity and an increase of 59 per cent. in value. The average price per ton at furnaces in 1917, as reported to the Survey, was $27.29, compared with $16.96 in 1916, an increase of 61 per cent. The production of pig iron, including ferro-alloys, was 38,647,397 gross tons in 1917, compared with 39,434,797 gross tons in 1916, a decrease of 4.5 per cent., according to figures published by the American Iron and Steel Institute, March 18, 1918.

Jan 12, 1918

By E. G. Leonardon, C. Schlumberger, M. Schlumberger

The authors give a definition of the various types of corrosion that may affect a metallic conductor buried in the ground, namely: 1. The metallic conductor may be attacked by the surrounding soil. This phenomenon is purely local and is called by them soil corrosiveness. 2. The metallic conductor may connect two regions of the ground when the electrolytes have a different composition. An electrical current will then be generated and certain zones of the conductor will be oxidized. This is autogalvanic corrosion. 3. Stray current may flow in the ground and enter the conductor in certain sections and leave it in others, thus causing oxidization in certain zones; this is electrolytic corrosion. The soil corrosiveness has been studied extensively by the United States Bureau of Standards and the authors give a summary of the work carried out and results obtained along this line. In autogalvanic corrosion it has been shown, by the investigation of buried pipes, that the zones of corrosion are associated with the zones of egress of the electric current (anodic zones). The location of these zones can be determined by measuring at the surface of the ground the difference of potential that exists along the path of the pipe. This work is performed easily and quickly with the apparatus invented by the authors for the exploration of conductive orebodies. The problem of electrolytic corrosion is a difficult one because it is a question of stray current which may vary in direction and intemsity at every instant. Therefore the components of the electrical field must be known at a given station and compared with the components of the clectrical field at another station, at the same moment. This is achieved by a rccording apparatus that will register the variations of the intensity of the electrlc current along two rectangular directions, during several minutes

Jan 1, 1934

By W. B. Heroy

The rapid development of transportation routes on the African continent in recent years has greatly stimulated the demand for motor fuels and this in turn has led to more extensive exploration of such limited portions of the continent as seem to give promise of commercial oil production. In 1930, however, only two countries were classed as producers of petroleum and only one, Egypt, attained any importance. Egypt The petroleum production of Egypt is derived from the Gemsah and Hurghada fields on the west coast of the Red Sea and the Abu Durba, on its eastern shore in the Sinai peninsula. The Gemsah field, which began to produce commercially in 1912, has now practically ceased production, owing to the invasion of salt water. The Hurghada field has been producing since October, 1914. It now has about 60 producing wells. During 1929, a deeper sand with flowing produition was discovered in the eastern part of the field, producing oil of lighter gravity and free from water. The Abu Durba field was discovered by the exploration work of the Egyptian Government in 1918, oil having been found at a depth of 172 ft. This field has now 15 producing wells but a very small production. The production of these Egyptian fields over the last five years, is as follows: Metric Tons Metric Tons 1926......................... 172,881 1929....................... 271,520 1927......................... 184,557 1930....................... 277,146 1928......................... 269,324 This oil was all produced by the Anglo-Egyptian Oilfields Ltd., a constituent corporation of the Royal Dutch Shell group. During the year 1930 the Egyptian Government was engaged in geophysical prospecting of reserved areas along the Red Sea coast. Other Countries Soma1iland.—A geological survey of Somaliland was undertaken by the Somaliland Petroleum Co., Ltd., a subsidiary of the Royal Dutch

Jan 1, 1931

J. S. UNGER, ? Pittsburgh, Pa. (written discussion ?).-Firebricks intended for, the same purpose, but supplied by different manufacturers, may be of entirely different clays, contain different proportions of flint, calcined and plastic clays; the particles may vary widely in size; the water used to make the brick will vary; the pressure in molding will vary, depend-ing on whether the brick is hand made or power pressed; and the degree of burning in the same kiln will differ. These variables affect the melting point and the strength of the brick when heated. An important property, of a firebrick is its ability to resist heat and, at the same time, weight or load without serious deformation. The soft-ening point and the melting point of a firebrick may be several hundred degrees apart, and two bricks may show considerable difference in their softening points, but the melting points may be approximately the same. Bricks are not usually employed at temperatures close to their melting points. If they must withstand very high temperatures, the firebrick is discarded and a brick of more refractory material is used. Under these conditions' it is doubtful whether the determination of the melting point of a brick has much practical value. If the determination of the melting point is necessary, the test should he made on a portion of the original brick and not on a specially prepared sample. A small triangular pyramid with a base about 1 1/2 in. and 3 in. high can be sawed from the corner of the brick with a thin-bladed car-borundum wheel, without injuring or destroying the size of particles, the bond, or degree of burning of the original brick. This specimen can then he compared with standard Seger cones or tested by any other method desired.

Jan 12, 1919

By Frank C. Greene

The principal event in the development of oil and gas in Missouri in 1942 was the drilling of the Cities Service Oil Company's No. I Jim Cook, in the northwest corner, NW. 1/4 sec. 32, T. 65 N., R. 39 W., Atchison County, in the northwest corner of Missouri. This well, not yet completed, bailed several barrels of free oil in about 27° Baume from a sand called the Bartlesville by those in charge, at a depth of 1450 ft. The well is on a block of leases obtained after the area, which is covered by several hundred feet of glacial drift, had been prospected by core drilling. Earlier in the year the same company drilled a well on the Glen Gray farm in the southwest corner, SW. 1/4 sec. 29, T. 65 N., R. 39 w., to a depth of 2427 ft. in the Hunton lime with a rotary drill. Oil stains in this hole led to the drilling of the second well. Table i .—-Wells Drilled for Oil and Gas in Missouri in 1942 Country Number of Number of County Oil Wells Gas Wells Dry Andrew.......... Atchison.......... I Bates............ 2 6 Caldwell.......... I 3 Cass............. I Clinton........... I Holt............. I Jackson.......... I I Knox............ I Nodaway......... I Platte............ 4 4 Ray.............. 5 Sullivan.......... I Totals.......... I 7 28 Otherwise drilling in Missouri was uneventful, with a total of only 36 Completions, of which one was a very small oil well, Seven were small gas wells and 28 were dry holes. The total footage drilled was 24,7541/2 ft., of which 14,0281/2 was by cable tools and 10,726 ft. by rotary. Twelve of the dry holes were drilled into Mississip-pian or older beds. Table I gives a summary of activities by counties.

Jan 1, 1943

By L. S. Pratt

In 1910 the author was engaged in a qualitative study of the radioactivity of several chemical substances and a few minerals. In the course of the work he studied the mineral allanite (obtained from granite ledges at Topsham, Maine), and found it to be appreciably radio-active. Recently the fact was brought to his attention that the radio-activity of allanite is not well known, although Hon. R. J. Strutt in 1905 published a list of radio-active minerals with their analyses, including allanite from Amherst County, Virginia.' In the work done, a standard type of electroscope was used, and the readings were made with a telescope, fitted with a scale, by means of which the rate of discharge could be readily determined. The natural "leak" of the instrument was carefully determined, and all results corrected accordingly. The method of study was as follows: The material to be tested was finely powdered, and spread over the bottom of a small, inactive pan. The electroscope was then charged, and the pan placed in position. The door of the instrument was closed, and the rate of discharge carefully determined. All results were reduced to common form to permit of comparison. It is to be noted that the materials tested were not used in strictly comparable quantities, such as if 1 g. of each had been used, but about the same quantity of powder was used (in the cases of the solid substances), so that the results are qualitatively accurate. The results obtained were the following, reduced to common form and corrected for the natural "leak" of the instrument used: Mm. in 6 Min. (on Scale) "Leak1'...................................... 1 Radium residue (in pan)....................... 720 Thorianite.................................... 62 Nernst mantle................................ 17 Uranium nitrate............................... 11 Allanite ...................................... 3

Jan 1, 1917

By Charles L. Hosler

My function here today is not to illuminate any particular subject but simply to welcome you to Penn State and to the College of Earth and Mineral Sciences. Our college is, of course, dedicated to the same thing to which most of you have dedicated your lives--the exploration of the earth, the extraction of materials from it, and the production of useful things from those materials. We have about 2,000 students engaged in studying in preparation for service in these activities at the present time. Like other colleges of our type, we've undergone a great expansion just at a time when university budgets are contracting. This creates an interesting situation as to how we can best use our resources. This, of course, is the thing a lot of you are going to be talking about here--how we can best use the world's resources. As you well know, the expectations of the people of the world are rising, and, with the numbers of people increasing and with finite resources, there never was a time in history when it was more important that we become "quantitative" in our discovery, estimation, extraction, and utilization of those resources. I think it is admirable and very timely that you are gathered together to discuss your various approaches to this particu¬lar problem of quantifying and making most efficient use of the resources of the world. Yours is sort of a hidden profession, not just because you actually go underground, but because the public in general is not aware of where the materials they use come from. If you are successful in your professions the public will continue to be unaware. Only if you fail will your essential function become patently obvious. I wish you success both in your professional pursuits and in this particular meeting.

Jan 1, 1977

ABIDE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has three major awards to make annually and one special prize for excellence in technical papers, as follows. The Robert W. Hunt Medal and Prize, The J. E. Johnson, Jr., Award, the James Douglas Medal, and The Lewisohn Platinum Prize to senior members. ROBERT W. HUNT MEDAL AND PRIZE The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting' ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules ? 1 The award shall consist of two prizes, first of a gold medal, second of a sum of money, a certificate to accompany each prize. The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal. 2 The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel The scope of the term "iron and steel" shall be determined by the sub-committee considering the awards In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt's main contributions to the industry have been in the improvement of production and quality of material

Jan 1, 1923

By Henry M. Howe

In my original paper, Piping and Segregation in Steel Ingots, I pointed out1 among other things that, in view of the slighter stretching (virtual expansion) of the crust, and greater opportunity for sagging, there should be less piping in broad than in narrow ingots, and less in slowly-cooled ingots, e.g., those cast in pre-heated sand molds, than in those which cool quickly, e.g., those cast in iron molds. A. A. Stevenson said that neither of these predictions agreed with his own experience. In particular, in a picture which he showed of a wide and of a narrow ingot cast from the same ladleful of steel: the wide ingot had certainly piped much more deeply than the narrow one. At the time I did not see the explanation of these discrepancies, but further reflection makes it evident. One of the most important elements in determining the depth of the pipe is the degree of " top-lag," that is, the degree to which the solidification of the top of the ingot lags behind that of the bottom. Through this lagging the steel of the upper part of the ingot is able to run down and fill the pipe below as fast as it forms. To the importance of this lagging I called attention in my original paper.' Sand us. Iron Molds.—If we compare two like ingots, one cast in an iron and the other in a sand mold, we see that the top-lag is much greater in the former than in the latter, because in the former the lower part of the ingot is cooling off fast while the metal is running into the upper part. It is perhaps easier to look at this as a case of the solidification of the hot-

Jan 1, 1910