TRANSACTIONS OF SECTION A, 461 
With the exception of the fourth line, the first six minima, all above the 
average, are followed by maxima above the average, and the last six minima, 
under the average, are followed by maxima under the average. It seems even 
possible that the unique exceptions in the fourth line are only apparent, for it 
concerns the first cycle of observations (1755-1761), and it is not unnatural to 
believe that the scale with which the sun-spots were then evaluated was not exactly 
the same as it is now. 
It would seem also that the interval of time between a minimum and the 
following maximum is smaller when the minimum is above the average and larger 
in the other case ; but I believe this fact has been already mentioned. 
If the relation indicated above holds true, we should be able to forecast one 
or two years in advance the general feature of a maximum of sun-spots from 
the observation of the preceding minimum. For instance, the last minimum (1902) 
has been very small ; it seems probable that the next maximum will be rather late 
and under the average. 
8. Relation between Pressure, Temperature, and Air Circulation in the 
- South Atlantic Ocean. By Commander C. Hepworrtn. 
9. On the Ultra-red Absorption Spectrum of Ozone and the Existence of that 
Gas in the Atmosphere. By Professor K, Anastrom. 
Already in 1861 Tyndall had found that, though oxygen transmits easily 
the radiation emitted from bodies of low temperature, this is by no means the 
case with its modification, ozone. In spite, however, of the evident importance 
of that discovery, it has not yet given rise to a more profound investigation of 
the character of this absorption, That question I have tried to solve by examin- 
ing the spectrum of ozone from A=0°6 » to A=14 ym" by means of the spectro- 
bolograph that I have constructed. The radiation was produced by a Nernst lamp 
of 110 volts. The absorption-tube, about 30 cm. in length, whose ends were 
closed by plates of rock salt, could be filled by 10 per cent. ozonised quite dry 
oxygen. 
vDhe result of that investigation is briefly the following :— 
In the portion of the spectrum between 0°6—4°6 yp, ozone does not seem to 
have any very considerable absorption-band, and as the radiation of the sun only 
in that part of the ultra-red spectrum has a greater intensity, it is evident that 
with regard to the quantitative absorption of solar radiation the ozone will not be 
of any greater importance. But in the following part of the spectrum ozone 
has several bands of great intensity, viz. :— 
A=48 yp. sh bs : C45 Sar, 
A=58p. : c ; : . Weaker. 
N==G$ 7a fis 9 : . ; . Uncertain. 
A=9'1-10°0 p ‘ : 5 . A very strong and extended band. 
It is evident from the position, the intensity, and the extension of these bands that 
the radiation from sources of low temperature must be strongly absorbed by 
ozone. With the already mentioned absorption-tube I have examined the absorp- 
tion of the integral radiation from the Nernst lamp as well as from a black surface 
at a temperature of 400°, 200°, and 100° C., and I have found it to be re- 
spectively 
1°8, 11°1 18°9, and 16°5. 
The question arises then: Is ozone really one of the constituents in the atmo- 
sphere ? 
It is well known that the existence of ozone in the atmosphere—except after 
thunderstorms—has been doubted, and the chemical reactions for, determining the 
quantity of ozone in the atmosphere are very uncertain, The knowledge of the 
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