338 TRANSACTIONS OF SECTION B. 
well-fitting glass stopper, passes through the rubber stopper and serves for the 
introduction of the ice-bulb. This last consists of a small sealed thin glass 
cylindrical bulb, containing a definite weight of distilled water and also as much 
silver gauze as possible. The last ensures rapid heat conduction, and makes 
the bulb heavy enough to sink in dense liquids. The bulb is suspended by a 
fine platinum wire. 
The liquid to be experimented with is introduced into the calorimeter by 
means of a standardisation pipette, and the apparatus is closed until constant 
temperature is attained. The ice-bulb has meanwhile been frozen in a mercury 
bath supported in an ordinary freezing-point apparatus. When the tempera- 
ture of the mercury is constant at from —3° to —4°, the bulb is removed by 
its suspension and rapidly introduced into the lower part of the stirring rod in 
the calorimeter. The liquid is then stirred by hand untii constant temperature 
is again attained, which usually requires about three minutes. Radiation cor- 
rections are then applied and the specific heat of the liquid calculated, the heat 
capacity of the ice-bulb being accurately known. ‘The experiments should be 
performed in a room regulated to constant temperature. 
The advantages claimed for the method are its simplicity, its rapidity, and 
its accuracy. Experiments with water at 25° C. gave consistent results agreeing 
to within 0-4 per cent. When ether was used, it was found necessary to coat the 
rubber stopper with tinfoil in order to protect it. The results with ether at 
25° C. agreed to within 14 per cent. (the vapour pressure of ether at this tem- 
perature is 545 mm.). The specific heats of several sulphuric-acid-water mixtures 
were also measured and compared with the classical results of J. Thomsen. The 
average divergence was less than one per cent. Further measurements with 
different liquids are now in progress. 
The apparatus described is not suitable for a viscous liquid (such as 
glycerine) owing to inefficient stirring. By having another liquid than water 
in the carrier-bulb, the scope of the method can probably be extended. 
8. lhe Influence of Weather Conditions upon the Amounts of Nitric Acid 
and of Nitrous Acid in the Rainfall near Melbourne, Australia. By 
V. G. ANDERSON. 
Daily determinations of the amounts of nitric acid and of nitrous acid in 
the rainfall at Canterbury, near Melbourne, have been made since November 1, 
1912. The results to February 28, 1914, when correlated with meteorological 
data for Melbourne and daily isobaric charts of Australia, reveal the existence 
of a relation between weather conditions and the amounts of nitrogen acids in 
rain-water. 
The concentration of nitric acid reached a maximum in summer, a minimum 
in winter, and an intermediate position during autumn and spring. The 
concentration of nitrous acid reached a maximum in winter, and a minimum 
in summer. The ratio of nitric nitrogen to nitrous nitrogen was highest in 
summer and lowest in winter. On many occasions during winter the ratio was 
approximately as 1:1. A relation between atmospheric temperature and this 
ratio was noted. Its nature was shown by plotting the mean minimum tem- 
perature of each month with the mean monthly ratios, the curve being of the 
same type as those which express changes of chemical velocity with temperature. 
The ratio is doubled for equal increments of temperature. From the results it 
would appear that in rain-water nitric and nitrous acids are formed in equal 
molecular proportions, and that, if the ratio could be determined instantly, or 
before any change could ensue, it would invariably be as 1:1. In cold weather 
the velocity is retarded to such an extent that little change occurs even after 
comparatively long periods; hence the increased amounts of nitrous acid found 
in winter. In hot weather, the velocity being greatly increased, the residual 
amounts of nitrous acid are very small, nearly all having been converted into 
nitric acid. The facts point to atmospheric nitrogen peroxide as the source of 
nitric and nitrous acids in rain-water, as this gas reacts with water, forming 
these acids in’ equal molecular proportions. 
