7192 
that they lead to the observed values of the heat 
of dilution. 
The special significance of these relations lies in 
the strong support which they give to the theory 
that the molecules and ions of a salt in solution 
are associated or combined with the molecules of 
water. 
The Measurement of Temperature up to 1750° C. 
(Illustrated): ARTHUR L. Day. Introduced by 
Professor William F. Magie. 
The gas thermometer is the standard thermom- 
eter in terms of which all temperatures are defined. 
The gas thermometer problem at the present 
Stage of its development has become primarily a 
problem for experimental study with two definite 
purposes, one to increase the accuracy of the 
Measurements, the other to increase their range. 
The range through which temperatures can now be 
determined in terms of the fundamental definition 
(the expansion of gas under constant volume or 
pressure) has now reached nearly to the absolute 
zero downward, and to 1550°C. upward. The 
present investigation is concerned with the higher 
temperatures lying between 300° and 1550°. The 
accuracy attained in the present investigation 
within this region is about 0.2° in the vicinity of 
300° and 2° at 1550°. 
For the purpose of establishing temperatures of 
reference in this region for general use, the fol- 
lowing constants have been determined: 
Cadmium (melting point) ..... 320.8 6.1 
Zine (melting point) ......... 419.3 + 0.1 
Sulphur (boiling point) ....... 444.5 + 0.1 
Antimony (melting point) ..... 629.8+ 0.2 
Silver (melting point) ........ 960.0 = 0.7 
Gold (melting point) ......... 1062.4 + 0.8 
Copper (melting point) ....... 1082.6 + 0.8 
Li,SiO, (melting point) ...... « 1201.0 + 1.0 
Nickel (melting point) ....... 1452.3 + 2.0 
Palladium (melting point) .... 1549.2 + 2.0 
Platinum (melting point) ..... 1752.0 + 5.0 
_ Selective Scattering Reflection and Absorption by 
Resonating Gas Molecules (Mlustrated) : ROBERT 
WILLIAMS Wooo. 
Some Observations on the Transmission of Sound 
through Walls: ARTHUR GORDON WEBSTER. 
New Magnetic Charts of the Indian Ocean (Ilus- 
trated): Louis A. BAavEr. 
The charts exhibited embody the results of 
magnetic observations made during the summer 
and fall of 1911 on board the non-magnetic yacht 
Carnegie operating under the direction of Dr. L. 
SCIENCE 
[N.S. Vou. XXXV. No. 907 
A. Bauer, director of the department of terrestrial 
magnetism of the Carnegie Institution of Wash- 
ington. 
The necessity of the new charts arose from the 
exceptionally large errors found in the magnetic 
charts at present in use by mariners. Thus, for 
example, the errors in the charted compass direc- 
‘tions for two of the most recent charts approxi- 
mate respectively four degrees and six degrees, 
though one of the charts was issued as recently as 
1910. With the exception of a few values found 
by the vessel used in the Pacifie Ocean work, 
namely, the Galilee, these are the largest errors 
thus far revealed. In the portions of the Atlantic 
Ocean covered by the Carnegie the compass chart 
errors have generally been below two degrees, 
though running at times up to two and a half 
degrees. 
The chart errors in the compass directions are 
usually found to be systematic, that is, in the 
same direction for large stretches, and are to be 
ascribed largely to erroneous secular changes al- 
lowed for in attempting to bring previously ob- 
served values up to date. 
Thus, for example, by comparing the Carnegie 
values of 1911 with those obtained on board the 
German Antarctic vessel, the Gauss, in 1903, it is 
found that the north end of the compass moved to 
the eastward (hence diminished west declination) 
at the average rate of about 11’ per year off the 
southeast end of Africa, whereas in the vicinity 
of the islands of St. Paul and New Amsterdam in 
the Indian Ocean (lat. 35° 16’ S., long. 74° 46’ E.) 
it moved to the westward (increased west declina- 
tion) at the average rate of about 13’ per year. 
The charts give secular changes of only about 
one fourth of these amounts, so that the error of 
reduction in but ten years amounts almost to 2°. 
It is doubtless due to these large secular changes 
disclosed in the Indian Ocean, and especially their 
rapid variation with geographic position, that the 
large errors mentioned have crept into the charts. 
The errors in the other magnetic elements, while 
of less importance to the mariner, are of conse- 
quence to theoretical investigations regarding the 
earth’s magnetism. In the magnetic dip, the 
errors on the present cruise haye amounted at 
times to 4°, and in the horizontal intensity to 
about one twentieth part. While some of the 
results derived from previous analyses of the 
earth’s magnetic field have pointed to the possi- 
bility of large and more or less systematic chart 
errors, it was not suspected that they would reach 
