254 Scientific Intelligence. 



elliptical path was photographed on the sensitive plate. The 

 length of this path changed with the turning of the axis of the 

 shot. The distance of the trace from the middle of the plate and 

 the distance of the plate from the opening which admitted the 

 light, enabled one to compute the angle between the axis of the 

 shot and the snn's rays. In order to determine the turning of the 

 axis of the shot around a vertical and around a horizontal axis, 

 the curves obtained from two firings were combined. These 

 shots were directed under the same conditions of velocity in dif- 

 ferent directions in regard to the sun's rays. Diffuse daylight did 

 not affect the distinctness of the trace of the sun's image, for 

 plates allowed to remain in the shot for one-half hour showed 

 only a faint pin-hole photograph of the surrounding landscape. 

 Certain curves showed breaks in continuity which were due to 

 the passage of the shot by branches of trees which shielded the 

 sun's rays for an instant from the sensitive plate. The paper 

 contains a short mathematical discussion of Euler's equation with 

 the object of determining from the obtained data the air-resist- 

 ance moment. — Ann. der Physik unci Chemie, No. 1, 1893. 



J. T. 



6. A New Species of the Magnetic and Electrical Instruments. 

 — G. Quincke describes with figures, galvanometer and mag- 

 netometers which are of novel form, and which constitute a 

 departure from the types which are known to the scientific world. 

 The essential featm*e of the new form is a glass disc, supported 

 vertically. Around the rim of the disc, a wire or wires are 

 clamped and in a hole at the center of the glass disc .is suspended 

 a mirror with magnet. This arrangement can serve either as a 

 tangent galvanometer or as a magnetometer. It is evident that 

 movable coils can be placed on each side of the glass disc which 

 carries the suspended mirror. The extreme simplicity of these 

 forms will commend them to instructors in laboratories, who 

 desire accuracy combined with economical arrangements. The 

 author points out the many simple modifications of his idea, and 

 maintains that greater accuracy can be obtained by instruments 

 of his form than by those of the conventional type. Illustrations 

 accompany his article. — Ann. der Physik mid Chemie, No. 1, 

 1893, pp. 25-34. J. T. 



7. Refraction of 'electrical 'waves by alcohol. — H. O. G. Ellinger 

 has succeeded in showing the infraction of electrical waves by 

 alcohol. The liquid was enclosed in a wooden vessel made in 

 the form of a hollow prism. This prism was one meter high, one 

 meter and fifteen centimeters long. Its angle was 8° 16' and it 

 held 90 liters of alcohol. The measurement was carried out by 

 Hertz's arrangement of mirror and spark and an index of refrac- 

 tion of 4*9 was obtained which agrees with the theoretical result. 

 — Ann. der Physik und Chemie, No. 1, 1893, pp. 108-109. 



J. T. 



8. Absorption spectra. — Julius has by means of the bolome- 

 ter determined the wave-lengths of absorption bands of a great 



