Specifications for and methods of testing soaps

NOTES NEW

FROM

FORMS

ENCE

AND

THE

OF

INSTRUMENTS

AMOUNT By

U. S. BUREAU

E. R.

OF

FOR

COMBUSTIBLE

Weaver

OF STANDARDS.‘:’ SHOWING GAS

THE IN THE

PRESAIR.’

and E. E. Weibel.

[ABSTRACT.]

iz STUDY has been made of the combustion of small amounts of gas in the air at the surface of electrically heated wires and the application of this phenomenon to the design of instruments for the purpose of detecting the presence and indicating the Xs a result of this study amount of combustible gas in the air. three types of instruments, each especially adapted to certain uses, have been designed, tested, and found to work satisfactorily. The action of one of these instruments depends upon a resistance change, one upon a heating effect upon an adjacent bimetallic strip, and one upon the light emitted from the heated wire. A discussion of the principles involved in the design of the instruments and specifications for their construction are given.

SPECIFICATIONS

FOR

AND

METHODS

OF

TESTING

SOAPS.’

[ABSTRM-T.]

THIS circular includes a general discussion of the composition of soap and the varieties of toilet, laundry, scouring and soft soaps for which specifications are proposed. These specifications cover milled toilet soap, white floating soap, liquid soap, shaving soap, salt-water soap, special-grade laundry soap, ordinary-grade laundry soap, chip soap, soap powder, hand grit soap, scouring soap (A), scouring soap (R) and automobile soap. The methods described include those for sampling deliveries, for preparation of the laboratory sample and for the following tests and determinations : Matter ‘volatile at Ioj” C. ; free alkali or acid; alkali as alkaline salts ; silicate; sulphate : matter insoluble in water _ ~_____ * Communicated by the Director. 1 Scientific Papers, No. 334. * Circular No. 62, ad edition. VOL. 187, iYo. 1122-56

71.5

U. S. BUREAU

746 (insoluble preparation acids ; total (qualitative

STANDARDSNOTES.

[J. F. I.

siliceous material) ; unsaponified saponifiable matter ; of total fatty acids; titer test; acid number of fatty alkali ; chloride ; rosin ; total anhydrous soap ; sugar test) ; feldspar and quartz ; potash and soda.

EFFECT By

OF

OF SOLAR RADIATION

UPON BALLOONS.

Junius David Edwards and Maurice Blaine Long. [ABSTRACT.]

THIS paper describes briefly the effect of solar radiation upon balloons and includes experimental measurements on typical balloon fabrics. Preliminary to the subject proper a summary is given of the characteristics of solar radiation and atmospheric conditions The radiation which have a direct relation to the problem. A series ‘characteristics of the fabrics themselves are discussed. of measurements on representative balloon fabrics showed an absorbing power for solar radiation varying from 45 to 93 per cent. The fundamental relations governing the temperature of balloon fabrics when exposed to solar radiation are outlined and the application of these to the calculation of balloon temperatures is discussed. The multiplicity of factors involved makes the calculation of such temperature of very limited value, but by means of measurements on a model balloon the magnitude and distribution of the temperatures involved, in both gas and fabric, are well illustrated. The temperature of the upper surface of the model balloon in bright sunlight under certain definite conditions, varied from 20’ C. to 39” C. The importance of the radiation characteristics of fabrics in governing buoyancy changes, in causing increased permeability of the fabric to hydrogen and in its effect on the life of the fabric is emphasized as a factor in the selection of fabrics for various Other factors affecting the selection of fabrics are purposes. summarized and their relation to the radiation characterisics is pointed out. aTechnologic

Papers,

No. 138.