1895.] Mineralogy. 267 
Universal Goniometer.—A very similar instrument to the Gold- 
schmidt goniometer just described is the Universal goniometer invented 
by von Federow.’ In this instrument the telescope is also the collima- 
tor, the signal being located in the side of the telescope and its image 
reflected to the crystal face by means of a prism. When the face is 
normal to the axis of the telescope the image is reflected back over its 
own path and brought to a focus on the cross hairs which are located 
just behind the prism. The credit for priority in the important inven- 
tion of the goniometer with two circles, and the method of measuring 
crystals by the location of the poles of their faces, clearly belongs to 
v. Federow, as a short description of his instrument was published in 
the Russian language in 1889.4 It is impossible in this space to re- 
view so important a paper as the one under consideration. It isa treatise. 
of some 140 pages on the calculation and projection of crystals from 
measurements with the universal goniometer. It contains suggestions 
for the renaming of crystal forms and the modification of the Miller’s 
symbols in the interests of greater uniformity in the system. 
Miers’s Inverted Goniometer.—Miers® has modified the Fuess 
goniometer with horizontal circle in such a way as to have the crystal 
held at the lower instead of the upper end of the axis of the instru- 
ment, and hence below the disc. The crystal may be measured im- 
mersed in a liquid which is contained in a rectangular trough with 
plate glass sides. The collimator and telescope tubes are placed at 
right angles to one another, their axes being also normal to adjacent 
sides of the trough. The liquid in the trough may be a concentrated 
solution of the crystal’s substance, so that changes in the form of the 
crystal during growth may be observed and measured. The trough is 
supported on a small table which can be raised or lowered at will. 
Some very important observations which Miers has made with this 
instrument will be reviewed in another place. 
New Goniometer Lamp.—Goldschmidt® describes a new gonio- 
meter lamp which he has found useful also for photo-micrographic 
work. The burner is an Auer or Welsbach burner (Auer’sche Gliih- 
licht) which is specially suited to the purpose because of its strong and 
3 Zeitsch. f. Kryst., xxi, pp. 574-714, 1893 
t Verhandl. k. mineral. Gesellsch. St. Petersburg, xxvi, pp. 458--460, Novem- 
ber, 1889. 
Nea pp. 411--412, Aug. 23, 1894 
6 Zeitsch. f. Kryst., xxiii, pp. 149-151, 1894. 
