. 
®, 
418 Scientific Intelligence. 
For objective representation A is connected with a glass bell closed by 
a fine membrane, the bell and membrane tuned in unison with the tone 
experimented with; the sand on the membrane will not be moved wlten 
the tone-wave passes through both branches, but it will move as soon as 
one of the branches is closed. 
The same apparatus may also be connected with one of Kundt’s tubes 
described at p. 258 of this volume; and it has finally the great advan- 
tage that it can be very easily made by almost anyone—Pogg. Aunn., 
1866, exxviii, 177-192. @. H. 
j apparatus for the demonstration of the laws of falling bodies. 
(“Fall-machine ;” might it not be rendered “ fall-apparatus?”)—F. Lrp- 
PIcH of Gratz, Austria, has constructed an elegant, simple, and compen- 
ich can be attached to a table; by means of a fine string 
vertical spring, attached to the support by passing through its position of 
equilibrium, opens the very ingenious clamp hol ing the string, so that 
the frame commences its descent at the very moment the spring passes 
the vertical position. The light frame is covered with well-stretched 
sooted paper; the vertical spring oscillating parallel to this paper carries 
a fine point, which marks a wave-line e descending paper. The 
described in the times 1, 2, 3, ete? Drawin tangents at these points of 
interseetion the velocities are determined. Measuring the exact length 
of the fall during six oscillations gave 296:24™™, 296:05™™, 296°26™™, 
frame ; and finally refers to an apparatus of Laborde based upon the 
same idea, but less perfect in its realization. Sitzungsberichie, Wien, — 
Utes Me 
1865, II Abth., Bd. lii, p. 549-562; Z’[nstitut, 1866, p, 199 
1. Astro-phot J. 
The astro-photometer is described in Zéllner’s “ Grundziage einer allgemei- 
plate, f, Nicol’s d and e, through a doubl 2. to a plane glass 
Papas d get a gh a double convex lens, g, to a plane g 
plate inclined 45° toward these rays and the axis of the telescope, Of, 
reflecting the Image of a to i near that of the star seen in the telescope 
at &, The rotation of Nicol ¢ is red off on the graduated circle m, 
. 
