摘要:

The classification of wool fibers into standard grades is based entirely on the average diameter of the fibers. The diffraction of light by a bundle of parallel fibers was employed by Thomas Young in 1824 in a simple ingenious instrument for the rapid direct measurement of average diameter, but no thorough investigation has ever been made of the practical possibilities of this method in the routine grading of wool.In the present paper a new construction of Young's instrument (the eriometer) is described, and a critical study is made of the accuracy and adaptibility of the instrument in the averaging of a wide range of diameters as distributed in a group of fibers. Sources of error and limitations of the method are discussed.It is found that the eriometer average is in excellent agreement with comparable data obtained with the microscope. The method affords considerable opportunity for the further development of instruments to include additional features desirable in the study of wool or other textile fibers.

ISSN:0034-6748    

DOI:10.1063/1.1748788

出版商:AIP    

年代:1931

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748789

出版商:AIP    

年代:1931

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748790

出版商:AIP    

年代:1931

数据来源: AIP

摘要:

A shield designed for use in a spectrograph to prevent pre‐exposure and subsequent exposure of the photographic plate due to scattered light when a number of spectra are photographed on the same plate or film. The use of such a shield eliminates consequent errors in the densities of spectral lines as determined by a densitometer.

ISSN:0034-6748    

DOI:10.1063/1.1748791

出版商:AIP    

年代:1931

数据来源: AIP

摘要:

The instrument described is used to time races by the use of a microphone, a photoelectric cell, an amplifier, and a clock. The time is recorded in 1/120 of a second from the instant when the sound of the starting gun reaches the runner's ear to the instant when the runner's chest touches the tape at the finish.

ISSN:0034-6748    

DOI:10.1063/1.1748792

出版商:AIP    

年代:1931

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748793

出版商:AIP    

年代:1931

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748794

出版商:AIP    

年代:1931

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748795

出版商:AIP    

年代:1931

数据来源: AIP