294 BACON. 



tropical region has proved to be very actinic with regard to the decom- 

 position of oxalic acid. 22 



Duclaux states that oxalic acid undergoes a spontaneous decomposition in the 

 air, and especially when heated ; 1 cubic centimeters of a solution of oxalic acid 

 heated for four hours to 95° lost 2.0 per cent and in eight hours 5.2 per cent. 

 Neubauer 23 and Bizio -' both found that oxalic acid decomposes spontaneously. 



N 

 1 heated 20 cubic centimeters of 1f . oxalic acid to between 9,5° and 



100° for four hours, on a stem bath. There was absolutely no loss. 

 The older results are probably largely clue to the use of poor glassware ; 

 for Richardson 2r ' found that oxalic acid is quite stable if kept away 

 from light. Solutions of a strength below normal arc stable to prolonged 

 heating at 100.° 



N 

 In the first series of experiments 1 prepared a tt. solution of oxalic acid 



which was divided into several portions as follows: 



' N 



1. January 15, 1910. One portion of this — - oxalic acid was exposed to the 



sunlight for two days in a sealed tube in an atmosphere of hydrogen. Tn that 

 time it had lost nothing and gave no test for hydrogen peroxide. 



N 



2. This portion of the — - oxalic acid was exposed in an open Erlenmeyer flask 



during the same time as sealed tube No. 1. The loss of oxalic acid was not 

 measurable and the solution gave a strong test for hydrogen peroxide. 



N 



3. This portion of the — oxalic acid was left in a flask which was exposed 



only to the diffuse light of the laboratory. Faint test for hydrogen peroxide. 



N 



4. This portion was diluted with an equal volume of water forming — oxalic 



acid, which was exposed to the diffuse, light of the laboratory as No. 3. 



22 The influence of sun spots on this phenomena has not yet been considered. 

 It may be a very important factor and in the future work on this subject an 

 attempt will be made to correlate known sun spot phenomena with the actinic 

 power of the sun as measured by these reactions we are studying. 



At Kieff it has been established that sun spot maxima are coincident with a 

 higher average temperature. For the work thus far accomplished in the Tropics 

 the results are somewhat contradictory. Koppen ascertained that in the Tropics 

 the temperature was by 0.32° lower during sun spot maxima than the average, 

 and that five years later, a year before the sun spot minimum, it reached its 

 maximum value of 0.41° above the average. However, Very found that the tem- 

 perature in very dry districts of the Tropics (near Port Darwin, 12° 28' S., and 

 near Alice Springs, 23° 38' S., Australia) is higher at sun spot maxima than at 

 minima. Therefore, from Very's measurements, it would appear that the solar 

 radiation is really more intense with larger sun spot numbers. Memery also noted 

 an instantaneous rise of temperature immediately a sun spot is first seen; however, 

 probably on account of the ionizing radiation, sun spot maxima are accompanied 

 by cloud formation in regions like the wet Tropics, which account for the cooling 

 effects noted above. 



--Ztschr. f. anal. Chem. (1870). 9, 392. 



24 Mew. (1867), 6, 52. 



2 >Jovrn. Chem. Soc. {London) (1849), 65, 457. 



