Detonation. Early in 1928, as part of the cooperative fuel research program, a special subcommittee was appointed to design "a composite engine representing average detonation requirements that may be recommended as a standard device for use in determining the detonation characteristics of motor fuels." The Bureau of Standards and seven other laboratories are represented on this committee which proceeded at once to design a test engine. A number of these engines have been built and each of the eight laboratories has received one. As soon as all the engines are in satisfactory operation, identical series of tests will be made by all laboratories on a group of six diverse fuels, to determine whether the engine can now be recommended for general use as a tentative standard test engine. If the engine proves satisfactory, a suitable test procedure will be developed.

Effect of Air Humidity on Engine Performance.-Tests, on an automobile engine and a truck engine, to determine the effect of humidity on engine performance were reported at the summer meeting of the Society of Automotive Engineers, and a paper entitled "Correcting Engine Tests for Humidity," by D. B. Brooks, will appear in a forthcoming issue of the Journal of Research. This work shows that failure to allow for the effect of differences in atmospheric humidity may introduce errors as great as would be occasioned by failure to allow for changes in barometric pressure. Under extreme conditions either correction may amount to nearly 10 per cent of the indicated power. Charts offering a simple means of obtaining the value of the humidity from readings of wet and dry bulb thermometers have been prepared. A continuation of the engine work has been requested by the Navy. Publications.-Correcting Engine Tests for Humidity, D. B. Brooks, N. A. C. A. Technical Note No. 309, June, 1929. Horsepower Correction for Atmospheric Humidity, D. B. Brooks, S. A. E. Journal, 25, p. 277, 1929.

Automotive Headlighting. Cooperation with the Society of Automotive Engineers in studying headlighting from the automobile driver's point of view has been continued. As an improvement on the instrument, mentioned in the 1929 Yearbook, for obtaining statistical data on glare, a multiple-element windshield photometer has been developed which has six unequally illuminated "grease spots." This enables the driver to estimate the approximate intensity of the light coming into his eyes from any approaching car. Preliminary observations indicate that an average driver can not consistently detect a change of less than 4 candlepower in a 21 candlepower bulb in his own headlamps.

Publications.-Automotive Headlight Requirements from the Driver's Point of View, H. C. Dickinson and H. H. Allen, Trans. Ill. Eng. Soc., 24, p. 15, 1929.

BUILDING AND HOUSING

Building Code Committee. The advisory building code committee, made up of prominent architects and engineers, has continued the preparation of basic recommendations. It serves as a focal point for work upon the minimum requirements for a uniform building code. Its recommendations have found their way into the building codes of more than 200 groups, but have as yet touched upon only isolated features of the subject, successive completed reports having dealt with small dwelling construction, masonry walls, live load assump

tions, form of arrangement, working stresses, and fire resistance. It is now time to take preliminary steps toward a consolidation of the work, and to include new matter, so that a fairly complete set of minimum requirements may be established.

During the year the committee has made a survey of the age of existing local building codes, and has made some study of the numbers of persons employed in various municipal departments in charge of building, and of their duties. Its subcommittee on plumbing has studied reports of peak loads of plumbing systems, the records of installations of plumbing in high structures, and the uses to which various sizes of pipe may reasonably be put; and has prepared Recommended Minimum Requirements for Plumbing, which appeared in February, 1929.

A tendency toward the preparation of regional codes has shown considerable development. This is good, provided a balanced consideration is given to all interests.

The work of the committee has been immeasurably facilitated by the assistance of professional societies, standardization bodies, and building material organizations.

Small-House Survey.-A study of representative small dwellings in 32 cities has been conducted during the year. Houses were inspected in the following cities, widely separated, so that the results obtained may be applicable to the entire country:

The analysis of these dwellings covered over 400 items of design, construction, and equipment. In the report the houses are classified by type of architecture, size of house, size of lot, house price, lot value, number of stories, number of rooms on each floor, cubical contents, location and type of utilities, type of garage, and improvements about the house and underground. Data are given showing height above grade, portion of basement excavated, thickness of foundations, roof overhangs, room sizes, ceiling heights, sizes and spans of joists, girders and rafters, breadth of stair treads, height of risers, and sizes of flues. The plans are indicated by a classification according to the relative locations of living room and bath, direct or indirect passage to kitchen, size or omission of vestibule and front hall, point of origin of main stairs, and type and location of porches. Construction methods used in different cities are outlined, and all construction materials used are listed. Wall treatment and equipment of all kinds are listed, with an indication whether the items are furnished with the building or not.

These data will show both builders and buyers what constitutes a modern small dwelling, and it is believed that they will make possible the establishing of improved standards of design, construction, and

equipment. This does not mean that any effort will be made to make small houses conform to a uniform, and possibly uninteresting, pattern, but rather to insure that each shall satisfy all those conditions that are considered essential to present-day homes of the type it represents. Such standards will not only be of value in the remodeling now in progress, but will reduce the need for remodeling in the future.

Home Financing.-Although the proportion of local funds used in home financing is great, even local methods and practices vary greatly. Plans submitted by a half-dozen banks or mortgage agencies for financing the same property may so vary in form and rate that an actuary would have difficulty in reducing them to a common basis. The situation is particularly acute in secondary financing; in one city rates varying as much as 200 per cent were found.

Conditions in various cities are being studied in the expectation of finding which methods and organizations have worked best. The data obtained will serve also to call attention to the need and the possibility of improvement.

Absorption of Sound. The acoustic properties of most auditoriums can be improved by a suitable addition and distribution of materials that absorb sound, and those of many can not be regarded as satisfactory until such addition and distribution have been made. The subject has acquired added interest since the advent of sound pictures. Two methods have been used for measuring the absorption of sound: (1) The reverberation method, which requires large samples, and (2) the tube method, in which small samples can be used. It has been found that the latter is suitable only for comparing similar materials, while the first may be used when absolute values are desired.

Heat Transfer Through Building Walls.-The rates at which heat is transferred through the more common types of building walls have been measured. The conductances found for some typical walls are given in the table, in terms of B. t. u. per hour, per square foot, per degree Fahrenheit difference in temperature between the surfaces. They refer to a mean temperature of 50° F.

Type of wall

8-inch brick, 4-inch plaster

8-inch hollow tile, 34-inch plaster..

8-inch brick, inside furring, wood lath, and plaster...

8-inch hollow tile, stucco, inside furring, wood lath, and plaster. Wood lath and plaster, studs, sheathing, paper, shingles..

CEMENT AND CONCRETE

Cement Inspection and Testing. During the year the bureau sampled 1,290,542 barrels of cement and shipped 1,073,590 barrels for various Government departments.

Cast Stone. A study of the physical properties of commercial cast stone has been made on a number of samples secured from all parts of the United States. This was in connection with the preparation of a Federal specification for this commodity. The properties of the several samples varied considerably. The number of cycles of freezing and thawing that the specimens underwent before any signs of disintegration were noticed varied from 15 to over 500.

Bond between Motar and Brick.-Cooperating with the American Face Brick Association, an investigation of the durability of the bond

between mortar and brick has been started. Tests are made to determine how the quality of the bond after a few months exposure to certain specified consitions is affected by (1) the moisture content and the rate of absorption of the brick, (2) the moisture content of the brick when bonded, and (3) the initial curing conditions. The exposures to be studied include dry, saturated, and outdoor storage, and 50 cycles of freezing and thawing.

Waterproofing Compounds.-Commercial damp-proofing and waterproofing compounds are being studied. The treated concrete specimens are 2 inches in thickness, and are made in a definite manner. After curing for seven days they are subjected to a water pressure of 20 pounds per square inch, and the permeability is determined in terms of the amount of water that passes through the specimen in a given time. Measurements will be made at all ages, up to one year. The several compounds differ considerably in effectiveness.

Arlington Memorial Bridge.-In conjunction with the Arlington Memorial Bridge Commission measurements are being made of the temperatures and deformations in one of the reinforced concrete arch spans of the bridge. Measurements were begun at the time the concrete was placed, and will continue for at least one year. Both the elastic and the inelastic deformations are being determined, and the measurements are planned so as to furnish a check on the reliability of the results of tests on small-scale models. Observations are being made of (1) the temperature, during and subsequent to the hardening of the concrete; (2) the deformations of the arch barrel due to changes in loading and temperature; (3) the rotations of the piers; and (4) the effectiveness of the expansion joints.

Cement Reference Laboratory.-In cooperation with the committee on cement of the American Society for Testing Materials there has been established a laboratory to deal with the various difficulties encountered in the testing of cement. A staff has been assembled and the laboratory equipped; it is now ready for operation. Instructions in proper methods of testing will be given to employees of cement laboratories throughout the country; equipment used in testing will be calibrated, and new test methods will be studied.

CERTIFICATION AND LABELING

State and other public purchasing agencies frequently seek the aid of the Department of Commerce in the formulation of standards, specifications, and tests for their purchases. This, and the necessity for providing specifications for the Federal Government itself, has led to the preparation of Federal specifications covering many commodities. (See p. 101.)

In order to facilitate the use of these specifications by public purchasers of all kinds-Federal, State, county, municipal-a "certification plan" is being applied to certain selected commodities. For each set of Federal specifications for each of these commodities the National Bureau of Standards issues a list of those manufacturers who, when so requested, are willing to certify and to guarantee to the purchaser that the material supplied complies with the requirements of the corresponding Federal specification. The name of a manufacturer is listed only at his own request. To date 267 such lists, representing over 7,800 requests received from about 2,000 firms, have been compiled, as indicated in the accompanying table.

In addition to Federal specifications, commercial standards are set up by industry itself, acting through representatives of the producers, distributors, and consumers, both contract and over-the-counter. These serve as the basis of trade; and manufacturers, dealers, and users are asked to limit their transactions in these commodities, in so far as they can conveniently do so, to such as conform to the standards. The certification plan is applied to commercial standards only upon the request of a representative conference, and after it has been definitely agreed to by the manufacturers interested. To date it has been applied to 7 commercial standards, covering clinical thermometers, Stoddard sovlent, all-clay plumbing fixtures, pipe nipples (brass, steel, and wrought iron) and regain of mercerized cotton yarns. This represents the requests of 88 firms for 107 listings among the willing-to-certify manufacturers.

Some manufacturers are using self-identifying labels to set forth their guarantee that the quality of the goods to which they are attached complies with the requirements of designated, nationally recognized specifications or commercial standards; and some have stated that they are now using, or are planning to use, such labels, or their equivalent, with the following goods when so manufactured as to comply with Federal specifications: Dental alloys, dry cells, fireproof safes, gypsum, ink, linoleum, paint, pipe, Portland cement, soap, and textiles.

CHEMISTRY

Melting Points of Pure Materials.-The following melting points have been determined during the year: