220 Setentific Intelligence. 
of different intensity. It is found that the microphone, used in 
this way, is far more sensitive than the ear to changes of tone— 
that it can be used with great effect to study resonance—the 
reflexion of sound in different rooms, and the influence of the 
change of sernvars upon the propagation of sound waves. 
The author proposes to — nd his investigations. —Annalen der 
Phi ie und Chemie, No. 6, 1881, 
. Reversal of the lines or Metallic Vapors. —Professors Lrve- 
ING pias Dewar have succeeded in reversing ten of the brightest 
lines of iron, in the blue and violet, by passing an iron wire 
through- one "of the carbons between which the electric arc is 
formed. hen iron is put in a lime crucible through which the 
voltaic are is formed, and fragments of m agnesium are dropped 
in from time to time, most of the strong brie violet lines of iron 
are reversed. 1e Soames appears to supply a highly reduc- 
ing atmosphere, and to carry the Oe vapor with it. It also 
appears to produce a continous spectrum in certain parts, and 
against this the iron lines are netics depicted on the photo- 
a 
through a perforated pole reverses ‘certain lines (wave length 
2492 to 2480) and spreads out the lines into broad absorption 
bands. These effects are enhanced by leading into the crucible, 
thera. the perforated upper sabe a gentle stream of hydrogen 
g ature, June 30, 1881, p. 2 
7. Chan nge of State. ’—There ae to types of change of ‘state 
which are usually recognized: the ice water type, in which the 
on evan n of temperatur Mr. J. H. TING ° Sefends ae 
elting and freezing by sup- 
posing, on the theory of the passage of molecules, “that if the 
th 
state with the less vapor-tension.” The alteration of the melting 
point by pressure is explained by the supposition tha 
alters the vapor-tension, and therefore the rate of escap 
cules, and that this alteration is different for the two states. Mr. 
a new proof of Sir W. Thom- 
en 
tension at plane surfaces of a liquid and the Me Selon 
same liquid above its surface in capillary tubes. The 
result is deduced that if ice can be subjected to oesire while 
the surrounding water is not so subjected “the lowering of the 
ich appear to s support this theoretical conclusio A. possi 
ae of Professor Carnelly’s “Hot Ice” is deduced from 4 
