ISSN:0034-6748    

DOI:10.1063/1.1752295

出版商:AIP    

年代:1937

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1752296

出版商:AIP    

年代:1937

数据来源: AIP

摘要:

Rochelle salt electrometers may be used to advantage where space requirements demand a device of small size. They are useful if they are to operate in a high impedance circuit. They also serve to study conveniently the piezoelectric properties of Rochelle salt.

ISSN:0034-6748    

DOI:10.1063/1.1752297

出版商:AIP    

年代:1937

数据来源: AIP

摘要:

It has been shown that the pressure coefficient of a coil of wire depends on the size and construction of the coil as well as upon the composition of the wire. The linearity of the pressure‐resistance relation also depends on the size and type of coil. The effect of winding, of heat treating, and of pressure seasoning on the resistance and pressure coefficient of various coils has been determined and measurements have been made on the effect of temperature on the pressure coefficient of manganin. Convenient equations applicable to the ``fixed bridge'' method for measuring small resistance changes are presented.

ISSN:0034-6748    

DOI:10.1063/1.1752298

出版商:AIP    

年代:1937

数据来源: AIP

摘要:

A rugged type of astatic magnetometer has been designed and built for use in the shop and laboratory to measure susceptibility of materials. The sensitivity may be adjusted from 2×10−8to 1×10−5electromagnetic c.g.s. unit per scale division, allowing the measurement of volume susceptibility of practically any material.

ISSN:0034-6748    

DOI:10.1063/1.1752299

出版商:AIP    

年代:1937

数据来源: AIP

摘要:

A method is described for measuring the velocity of light with a relatively short base line. A Kerr cell modulates a light beam at very high frequencies and a photoelectric cell is used for detection of the modulations. The modulated light beam is divided into two portions by means of a half‐silvered mirror and the two parts sent over different optical paths. By noting the difference in path length required to produce a minimum of voltage in the tuned circuit of the photoelectric cell, and the frequency of modulation of the light, it is possible to measure the velocity of light with considerable precision. Modifications of this method are described and the theory developed. The mean result of a series of measurements involving 651 observations is given as 299,764 km/sec. ±15 km/sec. in vacuum.

ISSN:0034-6748    

DOI:10.1063/1.1752300

出版商:AIP    

年代:1937

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1752301

出版商:AIP    

年代:1937

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1752302

出版商:AIP    

年代:1937

数据来源: AIP

摘要:

An alternating current bridge and amplifier for continuous temperature control of furnaces and thermostats is described. The circuit is simple and portable and can be made from standard electrical equipment. The power output of the control circuit is doubled for a change of 0.03 percent in resistance of the regulating thermometer. Regulated power up to 500 watts may be obtained. The control circuit has been used to maintain the temperatures of an oil bath and a furnace constant within 0.03°C per hour.

ISSN:0034-6748    

DOI:10.1063/1.1752303

出版商:AIP    

年代:1937

数据来源: AIP

摘要:

A variety of different gases at different pressures have been introduced into a wire form proportional counter and the linearity of response over the entrance studied. It is found that this varies markedly with the nature and pressure of the gas, being very poor for gases which readily form negative ions and improving for almost all gases as the pressure is reduced. An incomplete explanation of the behavior of the counter in terms fo the formation of negative ions is given, which is useful as a qualitative guide. Suitable gases and pressures are recommended for various types of particle counting.

ISSN:0034-6748    

DOI:10.1063/1.1752304

出版商:AIP    

年代:1937

数据来源: AIP