Chapter IX: Statistics of Manufacturing. 289 (3)

[O] Based on Michelet’s estimate for 1845.

[P] Based on Behm-Wagner estimate for 1874.

[Q] Levasseur’s estimate for 1878.

[R] Royal Geographic Society estimate.

[S] Estimates of the Archiv für Eisenbahnwesen.

[T] Estimates of the United States Census Office.

[U] Estimates of the United States Geological Survey.

[V] Estimates of the “Mineral Industry.”

CONCRETE AND STEEL. 322

BY J. F. SPRINGER.

[New York author of articles in Applied Science.]

The life of properly made concrete is not known. However, specimens from the times of the Romans are yet in good condition. This material has very considerable ability to resist compression; it is practically fireproof and teredo proof; when properly protected it is probably but little deteriorated by weather changes; and, if properly made, it is probably inappreciably subject to chemical disintegration when submerged. But there is one palpable fault--it is weak when subjected to tensile stresses. On the other hand--steel has great tensile resistivity and is strong under transverse stress. These two materials--concrete and steel--supplement each other in valuable qualities. The possibility of using them in combination depends largely upon the fact that their co-efficients of expansion are practically the same for moderate thermal fluctuations. Steel is easily corroded. Nor is it strictly fireproof, as temperatures which are not excessive will induce bending and buckling. When it is surrounded by concrete, steel is protected against both fire and corrosion.

In many situations, steel would not alone supply the best material of construction. And the same remark applies to concrete. A striking instance is the case of the six new docks in Baltimore. Three of these had already been constructed of wood and stone, when it became evident that the building of the remaining three and of the long bulkhead which was part of the scheme along the same lines would entail a larger expense than the use of reinforced concrete construction. Steel by itself would have been impossible of consideration because of its susceptibility to corrosion. Concrete alone could not be used because 323 of the excessive cost of the increased amount of Portland cement. It is said, that a retaining wall of all concrete would have cost about $600 per linear foot. Reinforced concrete costs about $58 per foot.

Steel is used, not merely as a reinforcement, but as the material of forms. Used thus, it may, at times, not only retain the concrete in position but also prevent the action of the surrounding soil or water. The possibility of using steel for forms depends largely upon the fact that many applications of concrete are becoming standardized rapidly. Thus is permitted a re-use of the steel form that justifies the expense. But the employment of steel forms sometimes involves the use of steel in the handling of them. A further use, although perhaps more remote, is in connection with the arrangements for the handling of the mixed concrete and of the raw materials. Still more remote, but still a necessary application, is the use of steel and iron in the crushing mills and the like. When we look at the question and inform ourselves of the ramifications, it is not difficult to see that concrete and steel are materials whose engineering applications are mutually involved. Concrete is certainly replacing steel in some applications. But, notwithstanding this, these two are to be regarded as unopposed to each other on the whole.

When concrete is cast about steel, an adhesive bond ensues. But this is scarcely to be regarded as sufficient to enable the two to act as one under tensile stresses. A mechanical bond should be employed. This is the explanation of the somewhat complicated forms of standard reinforcement bars.

Concrete properly reinforced is an admirable material for factory construction. It permits of rapid erection, is fireproof, has a long life, is adapted to weather conditions, and is economical. The floors of concrete buildings are easily cleaned and do not develop splinters.

One of the large automobile factories--that of the Geo. N. Pierce 324 Company at Buffalo, N. Y.--is a good instance of the rapidity with which reinforced concrete buildings may be erected. Within seven months of the date of signing the contract with the Trussed Concrete Steel Company, Detroit, Mich., which employs the Kahn system of reinforcement, certain large structures were ready for use. The floor space here is 325,000 square feet. It was necessary to provide a number of large areas unbroken by supports. It was found possible to use girders having spans of 55 and 61 feet. When subjected to a load, a girder develops compressive strains above and tensile ones below. The concrete is well adapted to withstand the one, but not the other. In an ordinary bridge truss, there may be diagonals that are also under tensile stress. In the Kahn system of reinforcement, a horizontal bar from which rigidly attached diagonals extend upward and outward is provided with a view of enabling the girder to withstand the tensile stress. In accordance with this design the long girders were constructed. Girders providing runways for 3-ton cranes were also constructed. A load of 14 tons placed upon one of the reinforced concrete girders having a span of 25 feet induced a deflection of only 1/16 inch. This girder is 12 inches wide and 22 inches deep and its reinforcement consists of three 1 x 3 in. Kahn bars. Hollow tile was largely employed here in connection with the concrete.

What is known in the trade as the corrugated bar, supplied by the Corrugated Steel Bar Company is a steel reinforcing rod which provides shoulders by means of which the concrete is mechanically engaged. This general type of reinforcement is, however, not confined to this concern. By means of this style of bar, the engineer is able to secure the desired mechanical interlock. As the concrete and steel expand and contract they do so together--unless the temperature change is excessive--and so the relation between the two is maintained. Such standard types of reinforcing bars are applicable to multitudes of 325 construction. An interesting example is the railroad bridge over the Vermilion River near Danville, Illinois. There are three arches, the central one of which has a span of 100 feet. About 130 tons of corrugated bars were employed in the construction of this beautiful bridge.

Another good example of bridge construction is the bridge over the Maumee River near Waterville, Ohio. This structure follows the designs of the National Bridge Company. It has a width of 16 feet between copings and crosses the river at a point where it is 1,000 feet wide. It is said that this reinforced bridge will carry a load of 5 tons per linear foot. The arches are 12 in number, the longest having a span of 90 feet, and the shortest, one of 75 feet. The loading of a bridge arch produces a lateral thrust upon the piers. If the next arch is not loaded, then this thrust is unbalanced and must be cared for. This was done in this case by employing part of the 100 tons of reinforcement in a vertical position. This bridge having a very long expectation of life was built at a cost of $77,000. The total amount of concrete was about 9,200 cubic yards.

The city of Philadelphia has gone into the construction of city bridges of concrete in rather an extensive way. Among a total of 30 or more is the reinforced bridge across Poquessing Creek, having a span of 71 feet. This bridge is rather flat, having a rise of but 9½ feet. The reinforcement employed here consisted in part of angle bars placed in pairs to form a kind of T-bar. The principal reinforcement here was the arch ribs. These were each composed of two of the T-bars arranged one above the other in such manner that their points of nearest approach were at the crown. These were latticed together. Such ribs were placed 4 feet apart. Transversely disposed steel rods held the whole together. The mechanical interlock here depended upon was due, no doubt, to the mutual disposition of the various rods, etc.

A railway viaduct, one-half mile or more in length is another example 326 of the Kahn methods. This structure belongs to the Richmond & Chesapeake Railway and is located at Richmond, Va. There is a span of 70 feet which has girders nearly 6 feet deep. At another span the girders, probably of about the same depth, sagged but ⅛ inch upon removal of the falsework.

A style of reinforcement much used consists of a net-like fabric of metal. This is employed largely in floors to bind the whole mass together. In the manufacture of this netting, a Canadian company has found it desirable to repair the inevitable breakages of strands in manufacture by the use of the Davis-Bournonville Company’s oxyacetylene torch. It is said that welds can be made on the average of one in two minutes in the case of an ordinary weight of the fabric. This netting is made by expanding sheets of perforated metal from a narrow to a considerable width. It is during this expansion that the strands sometimes break.

Another style of floor reinforcement is the fabric made from wire. That floors properly reinforced are quite substantial may be judged from the case of the United States Fidelity & Guarantee Company. Their building in Baltimore was exposed to intense heat in the great fire of 1904. In fact, a considerable part of the side walls and the front fell, leaving floors of concrete. A load of brick giving a pressure of 300 pounds per square foot was arranged on one of the floors to a distance of 5 feet to each side of one of the girders. The deflection amounted to ⅛ inch. This was about 1/20 of 1 per cent of the span. This is an example of Hennibique construction.

Reference has already been made to the Kahn truss reinforcement. With the same general object in view, the Hennibique truss has been designed. There are two horizontal bars, one above the other. The upper is, however, not perfectly horizontal except near the center. Towards either side, this bar rises as it recedes from the center. 327 These two bars are enveloped by loose stirrups arranged vertically and at intervals. These are open at the top and closed below.

There are two varieties of piles--the bearing pile and the sheet pile. Their duties are quite different. One sustains a compressive load, the other withstands a transverse thrust. But concrete has been used for both kinds. In the case of the bearing pile, its own intrinsic qualities are eminently suitable. It has good compressive resistance; it is teredo proof, and has the prospect of long life whether conditions are wet, dry or a mixture of the two. Wood makes an admirable bearing pile, if constantly submerged, but it is a prey to the teredo. The necessity for constant submergence limits the usefulness of the wood pile. It must be cut off below the hydraulic level, and this necessitates carrying the foundation footings to a lower level than would otherwise ordinarily be the case. With the concrete bearing pile, on the contrary, the footings may be constructed at any level desired as the pile itself may be partly submerged and partly in the dry. However, the concrete pile may be subjected to other than compressive stresses, especially during its placement. And so, some reinforce it. Some, no doubt, have in view a possible buckling when in the ground, particularly if the surrounding soil is yielding. Reinforcement both longitudinal and transverse is employed. Longitudinal bars are arranged at intervals around and within the periphery. These may be bound together by separate hoops disposed along the length or by wire wound about the longitudinals in spirals. In the case of concrete sheet piling, the concrete supplies a surface and forms a protective covering to the imbedded reinforcement which is here a vital matter and consequently indispensable. In the dock improvements at Baltimore, to which reference has already been made, reinforced concrete sheet piling was largely used. The steel sheet pile could not well have been used here because of its 328 susceptibility to corrosion. The concrete slabs, 12 × 18 inches in cross-section perform the duty of retaining masses of earth in place both above and below the water line. There were certain other concrete constructional elements of an auxiliary character. The total reinforcement amounted to about 1,200 tons.

With regard to its fireproof qualities, an eloquent testimonial arises from the fact that the immense Marlborough-Blenheim Hotel at Atlantic City, a concrete and tile structure, is said to enjoy a saving of $18,000 per year in fire insurance premiums. The insurance is based on $600,000. This structure is 560 feet in length and has a width varying from 60 to 200 feet.

Reference has been made to the close identity of the co-efficients of expansion for steel and concrete for moderate intervals of temperature. While this is so, if the thermal range is considerable, the concrete and the steel cannot be expected to expand and contract together. In most engineering construction, the range is small, say 150 degrees F., but there are exceptions. One of these relates to the material used in tall chimneys. The hot gases which pass up these give rise to rather high temperatures. In fact, it is well-recognized practice to build a large part of such chimneys double, one shell enveloping another, with an air space between. Some four or five years ago what is, perhaps, the very tallest concrete chimney in the United States was built for the Colusa Parrot Mining & Smelting Company, Butte, Montana. It is 352½ feet high and has a flue 18 feet in diameter. A solid wall 1½ feet thick constitutes the base of 21 feet in height. Above this level, an air space 4 inches wide radially is arranged between two shells of 5 and 9 inches thick. The inner one is the thinner. The steel reinforcements used were T-bars. The footing is of reinforced concrete and rests upon a fill 18 feet deep. A further important factor which has to be considered is the serious effect 329 of repeated stresses. Partly because of this, it is recommended that a large factor of safety be adopted. Further, the best practice would seem to be in the direction of a complete divorce between the inner and outer shells all the way up and of a uniformity in wall thickness from bottom to top. Vertical cracks have been noted in some chimneys. This would indicate the advisability of strong circular reinforcement. It is thought that a tone concrete following the formula 1:2:2 is better for the outer shell than a cement mortar. It is said to be stronger, denser and more impervious to water than a mortar following the formula 1:3. In order to secure adhesion between layers, the fresh concrete should be applied wet and the old should perhaps be resurfaced by tooling.

The compressive resistivity of the usual concretes is considerable. However, in certain bridge construction in New York City, a need was felt for a concrete which should have a very high compressive resistance. And so experiments were made with a concrete formed by substituting wire nails for the crushed stone. About 60 tests were made with concrete following the formula 1:2:2⅔. The resulting material was quite heavy. A cubic foot weighed 196 pounds as compared with 130 to 160 pounds for ordinary concretes. Eighty-eight pounds of nails were used in one cubic foot bringing the cost to about $2.30. This was certainly very expensive material. But where extraordinary qualities are desired, we have to spend money. Cubes were cast measuring 6 inches on a side. These were tested to destruction at different stages of maturity. After the lapse of one week, the lowest crushing resistance obtained was 2,770 pounds per square inch and the highest 3,330 pounds. After one month, the minimum crushing strength was 3,050 pounds, the maximum 8,340 pounds, while the average was 5,645 pounds. When a year had gone by, it was found that four cubes gave an average of 10,410 pounds. However, the average resistance of 330 17,235 pounds was obtained in the case of cubes 15 months old.

Since concrete is but little affected by water and by fluctuations between wet and dry conditions, it is not at all remarkable that it has been employed for sewer and water tower construction. In the United States a high standpipe has been constructed at Attleboro, Massachusetts. This is 118 feet high and has an internal diameter of 50 feet. The wall varies from 18 inches in thickness at the bottom to 8 inches at the top. The concrete was made according to the formula 1:2:4. There is another tower 110 feet high and having an external diameter of about 35 feet. At Anaheim, California, a large tank together with its substructure has been constructed entirely of reinforced concrete. The floor of the tank is about 60 feet above the surface. The tank itself is 38 feet in height and 30 feet in diameter and has a wall varying in thickness from 5 to 3 inches. The reinforcement employed was the twisted steel bar.

In order to prevent corrosion of the reinforcement, it is thought necessary to guard against water entering and dissolving away the caustic lime contacting with the steel. One way would be to give the concrete itself a very dense character. Another is to fill the external pores with a bituminous or oleo-resinous paint. Or, an insoluble substance suited to fill the pores may be one of the ingredients when the concrete is mixed. Finally a flexible waterproof coating may be employed where conditions permit. As to the steel itself--it is desirable to have it uniform, as then reliance may be placed upon calculations. For this reason, one of the great concrete construction companies recommends mild steel as opposed to high carbon steel.

One of the great recommendations of concrete is that it permits wonderful rapidity of construction. We had an example of this in the 331 case of the Geo. N. Pierce automobile factory. Another was in connection with the construction of junction caissons for certain subsurface tubes of the tunnel of the Hudson Companies. These caissons were three in number and were located on the Jersey shore opposite New York City. These structures were quite large, being about 100 feet in length and having a width of about 45 feet. These caissons, one or two of which were put under air pressure, were constructed of concrete with steel reinforcement. The use of concrete in the tunnel system and in the Terminal Building has been very extensive. To complete the concrete construction, about half a million barrels of Portland cement, so it is thought, must be consumed. The Gatun Locks at Panama will require only about four times this amount. The twisted steel bars of the reinforcement have been used in large quantity.

The work on the water front at Baltimore to which reference has already been made involved a considerable variety of reinforced concrete construction. For retaining walls sheet piles were employed. These ordinarily had a face of 18 inches and a thickness of 12 inches and a length of 27 feet. As it was not necessary to retain the soil by an impervious bulkhead, these piles did not interlock. However, they had to resist a horizontal thrust, and so wales were strung along the outside at the top. These wales were themselves of concrete reinforced by means of imbedded lattice girders of steel. In position, the girders lay flat and thus gave their chief strength to the horizontal thrust. The wales were supported, in part, by concrete piers. These were placed by means of steel caissons. These cofferdams were of sheet steel 27 feet deep and were sunk by open air methods. When in place, the concrete was put in and the pier thus formed. An upward surface of the pier provides a means of absorbing the horizontal thrust of the wales. The piers themselves are, some of them, mutually tied together across the dock; others are tied to reinforced concrete piles sunk in 332 the body of the dock. The ties are themselves of reinforced concrete. The steel of the caissons served only as a mold. It is now a matter apparently of but little importance how soon it corrodes. The extensive concrete work at Baltimore was done by the Raymond Concrete Pile Company.

While the question of the teredo seems to have been a factor at Baltimore because of the probability of its presence in the harbor when certain sewerage improvements are carried out, this matter was really an insistent thing in connection with a wharf constructed by the United Fruit Company at Bocas del Toro in the Republic of Panama. This wharf is itself of reinforced concrete. But the bearing piles are what interest us. The native wooden piling, so it seems, would at this general location become seriously damaged by the teredo within a year. Some kinds of timber might be expected to have a longer life. The service of creosoted piles has been estimated as about 15 years. Besides, piles 70 feet in length were desired. This requirement put the ordinary reinforced concrete piles out of consideration. What was actually done was to use an untreated timber pile and then to encase it where it passed through the water in a reinforced concrete shell. This shell was made of such size as to allow a space between it and the enclosed wooden pile. A rich concrete was put in this space at the bottom and thus excluded the external water. Upon pumping out the retained water, the major portion of the space was filled with a lean concrete and a top layer of rich concrete then added in which the column reinforcement was placed. The steel used for reinforcement was in the main round bars of mild steel. The piles averaged 58 feet in length; the shells, 18.4 feet. The cost of these shells was $1.78 per linear foot. It is said that the cost of the untreated wooden pile together with its protective coating was not greater than what would have been the expense for a creosoted pile.

At both the Baltimore docks and the wharf in the tropics, concrete 333 is exposed to the action of sea water. But there is no violence in this action. However, a very large application of concrete construction has been recently carried out in a very much exposed maritime situation off the coast of Florida. It is 156 miles from the mainland to the island of Key West. Scattered along this interval are a number of islands, so that in reality the total linear amount of intervening land is about one-half the distance. Some of the water passages are only a few hundred feet in width; one is about 2½ miles wide. The greater portion of the aqueous route is of a shallow depth. But for about 6 miles the water reached depths up to 30 feet; and this in connection with an exposed situation. Reinforced concrete viaducts have been built to accommodate trains and resist the storms. A quarter million barrels of cement and about 5,700 tons of steel went into these works.

The viaduct from Long Key is 2 miles long and passed through water having a depth ranging from 13 to 20 feet. The floor of the Gulf is of coral. To construct a pier, about 30 piles would be driven in with their tops projecting up from the floor. A cofferdam would be sunk to include them and a seal of concrete 1 yard thick be placed. The water could now be pumped out and the form concreted. The reinforcement would, of course, be put in place before depositing this concrete. The pier would then be allowed 3 weeks to mature. The concrete was mixed with fresh water to avoid the effect of sea water on the steel. Corrugated bars were used in reinforcing the walls and the 184 arches. High water is 31 feet below the top of this structure, so that the track is well protected from the waves.

It may surprise some, but concrete has actually been used as the chief material in the construction of boats. A reinforced concrete boat was built thirteen years ago for use on the River Tiber in Italy. Not only the hull but posts and roof of the structure above deck were of 334 concrete. This house boat was 67 by 21 feet. Another Italian boat is the Liguria, a barge in actual service. It is 57 by 18 feet and is rated at 150 tons. The Gretchen is an American example of the stone boat. She has sailed over long distances on the Atlantic and was reputed as comparatively a rapid sailer in a heavy sea. Her reinforcement was a multitude of small rods. This boat drew 14 feet of water and was 65 feet long and had a beam measurement of 16 feet.

Concrete is an obvious material for coal pockets, especially because of its fireproof character. A further advantage is the avoidance of a large maintenance charge. At Charlestown (Boston), the Lehigh & Wilkes-Barre Coal Company had been expending about $1,000 yearly on repairs upon a coal pocket. This has now been replaced by a concrete structure having a capacity of 10,000 tons. It has a depth of 24 feet, and has a length of 182 feet and a width of 92 feet. It is founded upon 750 Simplex concrete piles. If wooden piling had been used, the amount of excavation thus necessitated would have been very considerable because it would have been necessary to cut them off 10 feet below the surface in conformity with the building laws. Moreover, about 2,000 wooden piles would have been required because of the limit of ten tons’ bearing capacity per pile. With the concrete piles, however, the footings for the columns were constructed with but little excavation. The columns, side walls, girders, beams, floors--pretty much everything except the roof--were of reinforced concrete. When a full load of coal is filled in on the floor, the weight per square yard is 18 tons.

A similar application is to the construction of grain elevators. Reinforced concrete has been used at Baltimore in two important buildings of this kind and also in the case of a third at Buffalo. The question of fire is here very important. The grain elevator of the Pennsylvania Railroad at Baltimore is the largest of the three and is 335 constructed to hold 1,000,000 bushels. There are 53 cylindrical bins having a common height of 79 feet. There are four rows of eight each. The remaining twenty-one bins occupy spaces in between, three rows seven in a row. The set of 32 have the larger size and measure 24.2 feet in internal diameter. The walls are 8 inches thick and have both vertical and circumferential reinforcement. The vertical reinforcement is round bars of 1⅜-inch diameter. The circumferential reinforcement consists of interlaced flat bars. By a patented device the bins were cast in sections. This mold would be attached to the heavier vertical reinforcement and jacked up as needed.

It is unnecessary to emphasize the fact that concrete while economical is not cheap. So that when large masses are used, it is advisable to reduce the expense by using what may be called “pudding stones.” At McCalls Ferry a large dam and adjoining power house span the Susquehanna River. This is a tremendous application of concrete. However, pudding stones were very properly employed in the construction of the great dam. Here steel was employed not so much to reinforce but to supply frames for the molding surfaces. Great pelican cranes of steel were also employed to handle the concrete, etc. The face of the dam is a double curve and thus required a precise mold. Sections of the dam, 40 feet in length, would be constructed to alternate with open spaces of the same length. When it was desired to close such open spaces, a great steel apron would be let down on the upstream face. Concrete could then be laid in the open space.

In all the applications of reinforced concrete with which our attention has so far been occupied, the case has either been one of well-recognized practice or closely related to such practice--with the possible exception of concrete barges. There are two other lines of engineering application in which it is very desirable to employ 336 concrete, but where we are scarcely entitled to regard its use as anything more than experimental. Reference is made to telegraph poles and cross-ties. If a concrete pole really proves adapted to its service, then we may expect a great reduction in maintenance expense. It is estimated that renewals of wooden poles in the United States cost yearly $13,000,000. The prospect of getting a pole which will not need renewal for a long period is certainly attractive. But the actual service is severe. This is due not so much to the load which must be carried as to the horizontal movements under wind pressure. But by using proper reinforcement, it is thought by some, the pole may be made to withstand the horizontal thrusts. Some experiments have been made of a type of pole recommended by the American Concrete Pole Company, Richmond, Indiana. Four vertical rods bound together by wire constitute the reinforcement. Such a pole 7 x 7 inches at the top and 12 x 12 inches at the bottom was tested to destruction. This pole was 30 feet long and had its butt end sunk 5 feet into the ground. The vertical rods were ⅝ inch in diameter and were bound with No. 9 wire. A horizontal thrust or pull at the top of 840 pounds accomplished a deflection of 6 inches. When this was increased to 1,780 pounds, the deflection amounted to 17 inches. When 2,800 pounds pressure was employed, the deflection was 30 inches accompanied by a slight cracking. A deflection of a full yard together with cracking at the ground line resulted from a pressure of 3,640 pounds. When 7,200 pounds pressure was employed, the cracking became bad and the deflection amounted to 60 inches. A cedar pole of the same size was deflected 11 inches by a pull of 840 pounds. With 1,780 pounds, the deflection was nearly a yard (33 inches); and with 2,200 pounds the pole broke about 3 feet from the ground. The problem of the telegraph pole will probably be solved, if this has not already been done. 337

With regard to the cross-tie the case is more difficult. Plain concrete slabs or beams cannot be used after the manner of the wooden tie because of their want of elasticity. What is called “center binding” would be disastrous to plain concrete. The rocking action of the passing load is also a factor which enters. One method of dealing with center binding is to divide the tie into two parts, connecting them with steel rods. The Corell tie is an example of this. In the Percival tie, the under part of the concrete block is given a sharpened edge. Beneath the rail itself, the cross-section is a kind of oval. There is longitudinal reinforcement in the form of four rods, three arranged at the top and one near the bottom. Three rods are bound with wire. There is a cushion block of wood which absorbs and distributes the shocks from the bottom of the rail. Screw spikes and metallic sockets are employed. Some three or more years ago a hundred such ties were put in service in a Texas railway. In June, 1909, seven only were found to have received serious injury. It is thought that this damage was scarcely chargeable to the ties themselves as when in position they were between wooden ones whose deterioration might easily have been the cause of undue disturbance being thrown on the concrete ties.

We have considered to a slight extent the use of steel as the material of concrete forms. This line of application, however, promises to become a very large one. Two notable constructions are now under way in which the steel form plays a large part. These are the great Gatun Locks of the Panama Canal and the Catskill Aqueduct. The three double locks at Gatun will require about 2,000,000 cubic yards of concrete. Each pair of locks is on a separate level and has three longitudinal walls. One separates the lock chambers. This central wall is 60 feet in width. It is not solid as so much concrete would not be required as 338 the water level is approached. Consequently, there is a kind of V-section which traverses it longitudinally. This is filled in except for three galleries--one for drainage, one for the electric wires and one for the men. There is a longitudinal culvert arranged below the fill in the body of the concrete wall. In the side walls of the lock chambers are other longitudinal culverts. From the central supply culvert transverse distributing culverts run off beneath the floors of the adjacent lock chambers. These have vertical outlets into the lock chambers themselves. Similarly, but for purposes of emptying the locks, the longitudinal culverts arranged along the outside are connected by transverse culverts and vertical openings with the lock chambers. The members of the two systems of transverse culverts alternate with each other. The main supply culvert has a diameter of 22 feet part of the way and of 18 feet part of the way. Now these many culverts, various in form and size, are to be molded in the mass concrete by means of steel forms. As originally announced, there would be 12 forms of open hearth boiler steel for the main supply culvert. Each of these weighs 177,000 pounds. One hundred forms were to be required. The two main outlet culverts of similar dimensions to the main supply culvert were thought to require 21 forms, each 12 feet in length and having a weight of 300,000 pounds. The transverse culverts were to require 100 forms, each having a length of 10 feet and a weight of 217,000 pounds. There were thus to be 133 forms having an aggregate weight of 15,000 tons. It is possible that there may be some modifications of this plan in minor particulars. The side walls of the lock chambers are to be mainly vertical planes having a height of, say, 81 feet. To retain the fresh concrete in place, 12 face plates, constructed of sheet steel are to be used. These are 7½ inches in thickness, having face dimensions 78 x 36 feet. Steel towers running on suitable tracks control these face plates. It is estimated that 339 towers and plates will have an aggregate weight of 26,000 tons. So that, quite apart from any possible reinforcement application, steel to the total of about 41,000 tons is to be used for forms and immediate accessories. But this 41,000 tons is not all. The concrete is to be cast in great monoliths and to retain the ends of these while the concrete is fresh, steel girders 6 feet high are to be employed. If these locks were to be of stone then steel would have played a rather subordinate part.

The Blaw Collapsible Steel Centering Company are engaged at Panama, but they are also applying their systems of molding concrete to the great aqueduct which is to supply New York City with water from the Catskill Mountain region on the other side of the Hudson River. A steel centering is used to give form to the interior. Steel forms are also employed to shape the upper part of the external surface. At Baltimore, more than three miles of sewer construction was carried out in accordance with the system of the same company. The centering used for one portion where the height was 11 feet and the width 12¼ feet (inside) was employed in 50-foot lengths. In 2 hours, 6 men could remove such a 50-foot section together with its falsework and have it in readiness for a repetition of its service. A typical half-round Blaw center consists of one or more steel plates bent to conform to a cross-section of a semi-circle. Turnbuckles retain this shell in position. If we are going to employ this form in sewer construction, we first dig out our trench to such dimensions and form as to furnish the mold for the outside surface of the lower part of the concrete sewer. We then lay concrete in a longitudinal strip along the bottom, giving the upper surface the form of a shallow gutter. When this is sufficiently hardened, the semi-circular center may be slid along it to suitable position. The center has its concavity opening upwards. The concrete of the invert of the sewer is now placed. The same or a 340 duplicate center may now be used to mold the interior of the upper part of the sewer.

Portland cement has been in use for a long time. But reinforced concrete is so modern that in some important lines of engineering application the fundamental data underlying practice are not fully determined. In what may be regarded as the first decade (1870-1880) of the considerable manufacture of Portland cement in the United States, the total amount produced was only 42,000 barrels. Fifty years and more would be required for the production of enough cement to construct the Gatun Locks. Over a decade would be necessary to yield enough cement for the operations of the Hudson Companies. The price at this period was about $3.00 per barrel. In 1908 it was 85 cents. But the production in this year was more than 1,200 times that in 1880. The value per year of the present output is about $50,000,000.

CHEMISTRY AND THE INDUSTRIES. 341

BY BENJAMIN BALL FREUD, B. S.

[Assistant Professor of Analytical and Organic Chemistry, Armour Institute of Technology.]

Chemistry has always been a utilitarian science, a science whose direct applications to our every-day interests has been on every side recognized. Even in the days of alchemy, that fantastic forerunner of our present science, her devotees were concerned with the changing of the base metals into the noble ones, of lead into silver, and of copper into gold, and also with the search for the philosopher’s stone, that mysterious something which would give perpetual youth.

From these workers arose in the course of the years, the facts and the theories which were incorporated into the science of chemistry. But it is not entirely to the alchemists that chemistry owes its development. By far the greater number of facts, if not of theories, came down to us through the traditional knowledge of the chemical industries. Numerous animal and vegetable products, such as sugar, starch, the oils, gums and resins, had been familiar commodities as long back as history records. And the ancients were informed in such typically chemical industries as that of dyeing with vegetable dyes, pigment manufacture, varnish making, soap making, paper making and the fermentation industries. In fact the science of chemistry as we have it today owes much more to these unknown workers in the industries who transmitted their chemical facts from father to son, than it does to the creations of the imaginations of those picturesque, if not so truthful, alchemists.

It is entirely impossible to divorce the science of chemistry from 342 its industrial applications. The science owes much to the industries. The industries owe even more to the science. And if that relationship has been very close in the past, it is much closer now than it ever was; and it is getting closer all the while. The utilitarianism of our age makes it absolutely necessary that the two shall be so united that the utmost of good shall result from the union.

The application of science in general, and of chemistry in particular, to the industries has this one general result. It takes that industry out of the “rule of thumb” class, and places it firmly on a sound basis. It is no longer conducted in a haphazard manner, but according to intelligent design, based on the most accurate scientific information. Of course the fierceness of business competition has ordered this change, more than any other factor. The pure science of chemistry would have developed without industrial applications, because there are investigators who are seeking the truth regardless of any of its immediate applications. But in the industries, it is a matter of dollars and cents. The most efficient is the winner. And the most efficient is the one who utilizes in his business all the scientific information that can be brought to bear on the subject, and who is always looking for new facts that can be applied.

Chemistry, then, is applied to the industries in two distinct ways, the first in discovery, in finding a new substance which can be used, or a new process by which some useful or necessary substance can be made; the second in improvement, in making a certain product better, or cheaper, in utilizing wastes, or in starting from cheaper raw materials.

There are but two kinds of industries: (a) Those which are based on processes which change the form of matter, such as the manufacture of furniture for example, and (b) those which are based on processes which change the composition of matter, such as the manufacture of Portland cement from clay and limestone. Now group “b” comprises 343 by far the greatest number of industries, and since the science of chemistry concerns itself with just those changes in the composition of matter, it is evident that most of our industries are chemical in their nature. We have but recently come to realize this. A list of such industries and operations which are essentially chemical would be found to include almost every industry that we can think of. I need only make mention of the subject of fuels, gas and coke, of cement, mortars, brick and other building materials; of petroleum and its products; of asphalt; of the products of the destructive distillation of wood; of cellulose and of paper; of pigments, resins, varnishes; of rubber; of soap, fats and the fatty oils; of gums; of sugar and of starch; of the textile industries and of the dyes; of leather and glue; of explosives; of the heavy chemical industries, the manufacture of acids, alkalies and salts; of the manufacture of glass and the ceramic industries; of the fermentation industries; of the manufacture and standardization of medicines; of the subject of soils and artificial fertilization; of the subject of foods, and of nutrition; of the subject of water, sewage and sanitation; of photography; of all the electro-chemical industries and processes; of the production of steel, of copper, of lead and of all the other metals. I need only mention this formidable array of subjects and industries to convince the most sceptical one that chemistry does in fact, concern us, directly or indirectly, in all of our activities.

As I have said previously, chemistry influences industry in two distinct ways: First, in the discovery of new substances and new processes; secondly, in the perfection of known substances and known processes. In either of these fields the chemist is proud of his record. The conquests are so numerous that he is at a loss as to how or where to begin if he would tell of them. The whole field of industrial chemistry is one succession of chemical achievements, mammoth industries that had their humble birth in the chemist’s test 344 tube, his beaker, or his retort; the wealth of by-products saved to the world from what was a few years ago sheer waste; and above all increased efficiency in the manufacture of all products. The chemist does not claim more than his due when he points out that his activity covers the whole field of our daily experiences, and that his activity has always been for the lessening of waste, for greater efficiency, in a word, for the development of civilization. To illustrate the points which have already been brought out, the story of the soda industry, the beginning of the modern chemical industries, can be used. The beginning is far back in another century, so intimately is the development of the soda industry bound up with the advance of civilization.

The value of what we now call the alkalies as detergent substances, was known from the earliest times. The first alkali recorded in history is burned lime, and was called “caustic” on account of its characteristic property. Caustic lime is but slightly soluble in water, hence its use is greatly limited. History fails to tell who it was who first solved the problem of making a more soluble alkali, but some one, early in the Middle Ages, discovered that by the action of caustic lime on the so-called potashes, the ashes which remained on burning wood, a very soluble caustic was formed. And to this, the long since forgotten chemist gave the name “caustic potash.” The chemistry of the discovery is as follows: All plants take potassium, a very light metal, in some form or other from the soil, to form the so-called mineral, or bony structure, in other words the skeleton, of the plant. When these plants are burned the potassium in the form of a salt, chiefly potassium carbonate, is formed in the ash. These potassium salts can be extracted by water, and recovered on the evaporation of the water. These potassium salts, the so-called “potashes,” were extensively used in the industries of the time, for example, in making soap, in making glass, in dyeing and in a score of 345 other minor ways. But even as our forests cannot now meet the demand for timber, so they could not then meet the demand for the “potashes,” for it requires a large amount of wood to give a comparatively small amount of potashes, the percentage of potassium salts in wood being very small indeed. Simultaneously with all this, in northern Spain, on the seacoast, a number of towns were engaged in burning sea weeds. It was found that the ashes of sea weeds while not the same as potashes, nevertheless could be substituted for them. This is historically recorded as the “barilla” industry. Barilla consisted of 5 per cent of carbonate of sodium, a metal very similar to potassium. Sodium does for sea plants just what potassium does for land plants. Barilla was merely a substitute for potashes, and a very poor substitute at that. But it was destined to offer the key that solved the whole problem. The chemists of that time showed the chemical similarity between the active ingredient of potashes, carbonate of potassium, and the active ingredient of barilla, carbonate of sodium. The demand for these alkalies made by the industries was incessant and ever-increasing. The chemists realized that the direct natural sources of the two, namely, the wood of the forest and the weeds of the sea, were and always would be, inadequate to meet the enormously growing demands of the industries. They saw that some other source would have to be discovered, or the bodies would have to be prepared artificially. They realized that while potashes were better than barilla, nevertheless potassium salts, the ingredients of potashes, were much less widely distributed in nature than the sodium salts, the ingredients of barilla. So they set out with the definite object of preparing sodium carbonate. In 1791 LeBlanc took out a patent for his now famous process. He was not the only one who worked on the problem; he happened to be the successful one.

This was the first of the great triumphs of chemistry in the industrial 346 field. The significant point in this story of soda, is that those industries which were using the alkalies had reached the limit of their development, because the supply of the alkalies was so limited. Remember, also, that those industries were fundamental ones. Some historian has said that you can measure the civilization of a people by the amount of soap it uses. And here, we see the soap industry of Europe, the seat of our present civilization, crippled for want of an alkali. The position of the chemist, his responsibility to society, is the significant thing in the story. Here was a crisis in the development of civilization, as important to us as the crisis of the battle of Marathon. Because the problem was solved in the retort, instead of on the battle plain, because the battle was fought by the quiet hand of the chemist, instead of by the fighting men of Greece, we do not hear so much of it. But it was a triumph, and the credit belongs to the chemist. To us, as much depended upon the result of the battle of the molecules in the retort, as upon the defeat of the great Darius.

Nor was this battle in the retort a tame one. LeBlanc’s method is an extremely complicated one. To conduct the process at all requires chemical knowledge of the most varied kind. And to apply the improvements that have been worked out in the laboratory, and to carry into practice the many subsidiary manufactures that have sprung from this main industry, demands so much technical ability that it has been said that this manufacture is not merely the foundation of the immense chemical industries of today, but is also the guiding spirit in them.

LeBlanc, of course, could not foretell the enormous development his industry was to attain. Nor could he conceive of the ramifications running from it into countless other activities of our present civilization. The manufacture of sulphuric acid, one of the most important products of modern industry, is intimately bound up with that of soda. And, in the manufacture of sulphuric acid, nitric acid 347 is required, and must be made. Hydrochloric acid is a by-product of the soda process, and was for a long time permitted to go to waste. Now it is one of the most valuable products of the LeBlanc soda process. It is used to make bleaching powder, potassium chlorate, and otherwise in the industries. Also, the alkaline waste from the soda process is rich in sulphur. This sulphur is now recovered and put on the market as such, helping to meet the demand for sulphur that the Sicilian mines cannot supply.

All those varied industries that were either created or fostered by the soda industry have made possible the almost fabulously complicated processes that are now carried out in the manufacture of the aniline dyes, the artificial odors, like vanillin whose complexity can be gathered from its formula, C_{6}H_{3}OHOCH_{3}CHO, which tells many things to the chemist, but not much to the layman, and the artificial febrifuges like antipyrin, whose formula is C_{11}H_{12}N_{2}O. All these chemical industries that are the outgrowth of the soda industry, and that are so dove-tailed with our civilization, have been built up on the science of chemistry, and worked out by chemists. I have selected this story of soda to show the commanding position held by the science of chemistry in directing the course of civilization. It shows, too, how the entire structure of that civilization is built around the contributions of the chemist.

As has been already said, it is impossible to separate chemistry from industry. The farther we go and the more we develop and the more complex our civilization becomes, the closer become the ties uniting science and industry. And as everything that deals with the change in composition of matter is chemistry, it is evident that chemistry is omnipresent. In the light of what it has accomplished, who shall say that it is not omnipotent?