C99. The Carbonization of Lubricating Oils.

After brief accounts of the nature and effects of "carbon" deposits in internal combustion engines, and of the chemical nature of petroleum oils, the theories concerning the cause of these deposits are discussed. The oxidation and cracking of petroleum are next taken up in some detail after which the methods for determining the "Waters carbon" and the 'Conradson carbon residue" are described. Other methods, including those depending on distillation, are touched upon. A brief summary of certain controversial papers closes the circular.

66

Croo. Nickel.

This Circular is one of a series describing the physical properties of metals together with a discussion of the relation of these properties to the composition and treatment of the material. In this one are described the properties of nickel and of its commercially important alloys; nickel-steel, ferronickel, copper-nickel, and nickel-chromium alloys.

CIOI. Physical Properties of Materials: I. Strengths and related Properties of Metals and Certain Other Engineering Materials.

This circular aims to present in readily accessible form, the best available data on the strengths and related properties of metals, alloys, and certain nonferrous materials. Among the materials treated are iron, carbon steels, alloy steels; wire and wire rope; semisteel; aluminum, copper, and miscellaneous metals and their alloys; rope, rubber, leather, and woods.

The tensile strength, proportional limit, percentage elongation in two inches, percentage reduction of area, Brinell and scleroscope hardness corresponding to a certain composition, density, and method of preparation are shown in most cases for the metals and alloys.

In addition, figures are shown in many instances for the compressive and shearing strengths, modulus of rupture and Erichsen value.

The circular also includes definitions of the properties treated and references to sources.

C102. Recommended Specification for Composite Thinner for Thinning Semipaste Paints when the Use of Straight Linseed Oil is not Justified.

This specification, prepared under the auspices of the Bureau of Standards, is recommended by the U. S. Interdepartmental Committee on Paint Specification Standardization. The specification gives the requirements as to appearance, color, odor, mixing with linseed oil, drying, toughness, nonvolatile matter, and acid number. It describes the methods of sampling and of laboratory examination, and the method of preparing the reagents used.

C103. Recommended Specification for Spar Varnish.

This specification, prepared under the auspices of the Bureau of Standards, is recommended by the U. S. Interdepartmental Committee on Paint Specification Standardization. The specification gives the requirements as to appearance, color, flash point, nonvolatile matter, "set to touch," dry hardening and toughening, bending toughness, working properties, water resistance, and durability. The methods of sampling and laboratory examination are given in detail.

C104. Recommended Specification for Asphalt Varnish.

This specification, prepared under the auspices of the Bureau of Standards, is recommended by the U. S. Interdepartmental Committee on Paint Specification Standardization. The specification gives the requirements as to appearance; color; flash point; action with linseed oil; solubility in carbon bisulphide; nonvolatile matter; fatty matter; "set to touch;" dry hardening and toughening; bending toughness; working properties; and resistance to water, to oil, and to mineral acids. The methods of sampling and laboratory examination are given in detail.

C105. Recommended Specification for Liquid Paint Drier.

This specification, prepared under the auspices of the Bureau of Standards, is recommended by the U. S. Interdepartmental Committee on Paint Specification Standardization. The specification gives a general statement regarding the composition, properties, and as to the requirements with respect to sediment, suspended matter, film, flash point, linseed oil mixing, and color. The methods of sampling and laboratory examination are given, as well as the basis of purchase.

C106. Lime-Definitions and Specifications.

General description of lime. Definition of trade terms. Recommended specification for masons' hydrated lime.

C107. The Testing of Paper.

Gives methods used at Bureau of Standards for determining the quality of paper, including the following tests: Weight, thickness, bursting strength, tensile strength, folding endurance, tearing strength, absorption, transparency, determination of loading and sizing material, and microscopical estimation of fiber content.

There is also given a general suggestion for specifications, a short bibliography, regulations regarding tests and suggestions for sampling.

C108. Gypsum-Properties, Definitions, and Uses.

Description of the general properties of gypsum products, definitions of trade terms and specifications.

C109. Sand-Lime Brick-Description and Specification.

General, nontechnical, description of sand-lime brick, with the specifications recommended by the Bureau.

C110. Specifications for Marine Sextants.

These specifications, incorporating standard practice in design and performance of sextants, are the basis for certificates issued by the Bureau of Standards. They cover the rigidity, durability, convenience of operation, and mechanical perfection of the instrument; range and accuracy of the scales; consistent tolerances for the mirrors, shade glasses, and telescopes; and provisions for adjustment and replacements.

New instruments are expected to conform closely with these specifications or represent improvements. The precision required of old instruments is placed somewhat below that required of new in order that those which are still serviceable and reliable may not be excluded from certification.

CIII. Recommended Specification for Flat Interior Lithopone Paint, White and Light Tints.

This specification, prepared under the auspices of the Bureau of Standards, is recommended by the U. S. Interdepartmental Committee on Paint Specification Standardization. The specification gives the requirements as to constituents, their maxima and minima, the methods of sampling and laboratory examination, including the analysis of the pigment and the preparation of the reagents.

C112. Telephone Service.

Service in general, service grades, service classification and service development are considered in an introductory section. The next four sections are descriptive of the telephone plant and its operation. These are followed by a section on telephone traffic which considers the handling of calls from a quantitative standpoint. The next section is of an analytical character and explains the relation of the elementary characteristics of telephone service to the grade of service. A section regarding public relations is included to cover commission regulation and a conclusion regarding the subject of service standards. A statistical section is appended.

C113. The Structure and Related Properties of Metals.

This Circular which replaces one of earlier date (No. 42, Metallographic Testing) is a comprehensive discussion of that phase of metallography indicated by the above title. The numerous examples which have been used throughout the test have been taken from the results of metallographic examinations made by the Bureau, of specimens submitted for examination as well as those used for research. The various methods for revealing the macrostructure as well as the meaning of the features revealed are discussed, and a list of reagents for revealing the microstructure included. By means of numerous "live" examples the conditions which affect the structure of metals are discussed, also the effect of structural features upon mechanical and chemical properties of metals. A rather comprehensive discussion of the applications of the microscopy of metals has been given. C114. Standard Specifications for Cotton Rubber-Lined Fire Hose.

The frequent calls made upon the Bureau of Standards for fire-hose specifications have resulted in the formulation of the standard specifications in this Circular These specifications were prepared by the Bureau in cooperation with technical experts appointed as representatives of the leading manufacturers of fire hose. The specifications have been officially endorsed by the Rubber Association of America. The topics covered include both physical and chemical laboratory requirements, hydraulic pressure tests on full lengths of hose, and of essential characteristics of both lining and jacket. Provision is made for the basis of payment and the interpretation of specifications and action in case of disputes.

C115. Recommended Specifications for Pneumatic Tires, Solid Tires, and Inner Tubes.

These specifications cover the requirements for pueumatic tires, solid tires, and inner tubes. Recommended by the Interdepartmental Committee on Specification Standardization, June 8, 1921.

These specifications are a revision of those prepared by the Bureau and now used by the War Department, Navy Department, Panama Canal, and the Treasury Department.

A tentative draft of the specifications was submitted to a large number of representatives of the tire industry, including the Rubber Association of America, and in the revision careful consideration was given to their recommendations.

C116. How to Get Better Service with Less Natural Gas in Domestic Gas Appliances.

This circular gives the principal conclusions from the laboratory and field investigations of the Bureau, on the correct use of natural gas in the home. Proper adjustment of appliances will make it possible to get better service with much less gas, and it will allow the gas pressure to be reduced to two ounces or less. Reduction in pressure will greatly reduce the leakage in the distributing systems and this with the saving in the homes will add a large number of years to the period that natural gas will be available for domestic use.

C117. Recommended Specification for Interior Varnish.

This specification, prepared under the auspices of the Bureau of Standards, is recommended by the U. S. Interdepartmental Committee on Paint Specification Standardization. The specification describes the acceptable varnish with respect to ease of application and the resulting elastic glossy coating, also the general characteristics including appearance, color, flash point, nonvolatile, set to touch," dry hardening, dryness for rubbing, toughness, working properties, and water resistance. The methods of sampling and laboratory examination are given and the basis of purchase prescribed.

C118. Recommended Specification for Limestone, Quicklime, and Hydrated Lime for Use in the Manufacture of Glass.

Requirements are given for three classes of lime, depending upon the quality of the glass to be made. Combined CaO and MgO is to be not less than 96, 91, and 83 per cent, respectively, for the three classes.

C119. Specifications for Lime Flint Glass Tumblers.

These specifications include dimensions for the article, with tolerances, a statement of quality required, tests for quality, basis of acceptance or rejection of order, and method of sampling. (These specifications have been accepted by the Army, Navy and Marine Corps, Panama Canal, Public Health Service, and General Supply Committee.)

HANDBOOKS

[For publications in following list that are out of print or procurable only from Superintendent of Documents, Government Printing Office, Washington, D. C., see the supplement to this circular.]

Hr. Manual of Inspection and Information for Weights and Measures Officials. (Superseding M1.)

This manual is designed primarily for official sealers and inspectors appointed to enforce weights and measures laws or ordinances, but it will also be of use to any one who has occasion to inspect and test weights and measures and weighing and measuring devices of the types ordinarily found in commercial use. It contains specifications and tolerances and complete instructions for the testing of all kinds of scales, length measures, liquid and dry capacity measures, etc.; general instructions concerning the enforcement of law; lists of standards and apparatus; a method of keeping office records, etc. Appendixes are included containing Federal weights and measures laws, with rules and regulations, the model State law in relation to weights and measures, a description of the metric system, and general tables, conversion tables, and tables of equivalents. (Nov. 14, 1918.) 246 pp. Price, 50 cents.

H2. National Safety Code for the Protection of the Heads and Eyes of Industrial Workers.

This is a set of rules designed to give mechanical and optical protection to the eyes of workers in certain occupations which involve eye hazard. The rules have been worked up in cooperation with a sectional committee of the American Engineering Standards Committee.

The rules are accompanied by a discussion intended to assist in their interpretation and application and to show the reasons for including some of them in the text. (Dec., 1920.) 64 pp. Price, 10 cents.

H3. National Electrical Safety Code. (Superseding C54.)

A code of rules for electrical construction and operation in four parts. Part I deals with electrical generating stations and substations and specifies appropriate guarding, isolation or grounding of live parts and machine frames and provides adequate working spaces. Part 2 deals with electrical overhead and underground line construction, specifying minimum clearances and strength of construction. Part 3 deals with utilization equipment in factories and elsewhere in a manner similar to Part 1. Part 4 gives operating rules for employers and employees in the electrical industry. A supplementary section gives rules for grounding equipment and lines. (Oct. 31, 1920.) 366 pp. Price (cloth bound), 40 cents.

H4. Discussion of the National Electrical Safety Code. (Superseding C54.)

This publication contains a discussion of the rules of the National Electrical Safety Code as published in Handbook No. 3. The discussion is intended to give the reasons for inserting some of the rules, to aid in the interpretation of the rules, to give suggestions as to how the rules may be applied and suggestions regarding practice involved in the rules. In the present edition, it has for convenience been segregated under a separate cover from the rules themselves. This discussion was originally included in Circular 54, but has been amplified and considerably extended in scope. (Oct. 31, 1920.) 330 pp. Price (cloth bound), 40 cents.