14 REPORT—1863. 
Brom. Phosph. | Chlor. Phosph.}| Chlor. Carb. 
QOpsdrvedaly iepbiniil voay onbpdieie = 237 348 *287 
Calculated from constituents .. . "250 304 "264 
These show merely a general resemblance between the observed and the calcu- 
lated energies. They form part of the ever-multiplying proofs, that though a 
chemical compound may be considered as haying a specific refractive energy com- 
posed of the specific refractive energies of its component elements, it is, as stated 
elsewhere, modified by the manner of combination. 
The specific refractive energy of chloride of ammonium appears to be *42. As 
calculated from Dulong’s numbers for nitrogen, hydrogen, and chlorine gases, it 
should be only 34 ; but as calculated from the specific refractive indices of ammonia 
and hydrochloric acid when liquefied by solution, it is -417. 
On a New Form of Syren. By W. Lavp. 
A disk of cardboard is perforated with 1682 holes, apportioned into twenty-four 
concentric circles, the fifteen interior ones being divided into regular, and the 
remainder into irregular, intervals. The former are divided in the followin 
proportions :—For every two holes in the first circle (counting from the eatin} 
there are 3 in the 2nd, 4 in the 3rd, 5 in the 4th, 6 in the 5th, 8 in the 6th, 10 in 
the 7th, 12 in the 8th, 16 in the 9th, 20 in the 10th, 24 in the 11th, 52 in the 12th, 
4O in the 13th, 48 in the 14th, and 64 inthe 15th. If with a small tube air is blown 
into these circles whilst the disk is in rapid rotation, a series of musical notes will 
be obtained, allied to each other in the relative proportion of the numbers. Look- 
ing at the outer portion of the disk, lines of holes are observed radiating from the 
centre, and dividing the disk into 24 equal parts; and, if the other holes were 
stopped, each of these rings would produce a single sound, the same as the 6th 
row of the inner series. This note will form the fundamental of all the harmonies. 
If a point is taken in the first of the external rings, and, starting from it, with a 
air of compasses the distance between it and the first intermediate hole is repeated 
bv times, it will correspond with four of the fundamental spaces; and if a single 
jet of air is forced through these holes whilst the disk is rotating, the idea con- 
veyed to the mind will be precisely the same as if two separate notes were sounded 
together—the two notes being a fundamental and its third, the proportions of the 
vibrations being as 5:4. The 2nd row is divided in the ratio of 4: 3—this will 
give a fundamental and its 4th (or subdominant); the 3rd row is divided as 3: 2, 
giving the fundamental and its fifth (or dominant); the 4th row, divided as 5: 3, 
gives a fundamental and its 6th ; the 5th row is as 7 : 4—this giving a fundamental 
and flat 7th; the 6th row has a combination of four holes, in the proportion of 
6:5:4:3—this will give a perfect chord of four notes; the 7th row has four holes, 
in the proportion of 8:6: 5:4—this will give a perfect chord with octave of the 
fundamental; the 8th row is divided in the proportion of 5:4:3, giving a per- 
fect major triad with inverted 5th; and the last row is divided in the proportion 
of 6:5:4, which forms a ee major triad. The exact intonation of the notes 
given out by the inner circles, and the exquisite harmonies produced by the outer 
ones, are remarkable, 
M. Soteiz’s Tenebroscope, for illustrating the Invisibility of Light. 
Exhibited and described by the Abbé Moreno. 
The instrument exhibited consisted of a tube with an opening at one end to be 
looked into, the other end closed, the inside well blackened, and a wide opening 
across the tube to admit strong light to pass only across. On looking in, all is 
perfectly dark, but a small trigger raises at pleasure a small ivory ball into the 
course of the rays, and its presence instantly reveals the existence of the crossing 
beam by reflecting a portion of its light. 
