SECTIONAL TRANSACTIONS.— A, B. 317 



In this paper a survey is given of recent work, notably that of W. P. Milne, for 

 the cases ^=4, 5. Another case, which is not general in the sense described above, 

 arises with the plane quintic curve (75=6). Here we have to investigate the 5-tangent 

 conies. Some progress can be made on the hnes of two methods which have proved 

 successful for the quartic, Hesse's discussion by means of a net of quadrics and 

 Geiser's generation from the cubic surface. 



SECTION B.— CHEMISTRY. 



(For reference to the publication elsewhere of communications entered in the 

 following list of transactions, see p. 427.) 



CAPE TOWN. 

 Tuesday, July 23. 



Presidential Address by Prof. G. Barger, F.R.S., on The Relation of 

 Organic Chemistry to Biology (followed by Discussion), (See p. 51.) 



Wednesday, July 24. 



Prof. B. DE St. J. van der 'Riet. ^Volatile Oils from South African 

 Plants. 



The volatile oils from (a) non-indigenous plants, particularly those from the oleo- 

 resin of the cluster pine, Pinus pinaster, and the citrus, and from (6) indigenous plants 

 have been investigated, and in some cases their constants determined. Of the latter 

 class some seventeen varieties have been dealt with, and the desirability of a more 

 complete investigation is emphasised. 



Dr. E. Sbuuehs.— Chemical Effects of Lunar Radiation. 



The hydrolysing effect of moonlight is shown by its action on films of boiled starch. 



By treating with iodine the faint shadow of a small opaque object can be printed 

 on paper dipped in starch solution, which has been exposed to the lunar rays. 



This effect is also seen when the surface of a leaf is similarly treated. The 

 phenomenon is most evident at times of maximum polarisation of the lunar radiation. 



The action is entirely a surface one, and is due to some correlation between the 

 orientation of the polarised light vibrations and that of the surface molecular layers 

 of the starch film, or of the physiological surface. 



This correlation was first suggested by the author at the Liverpool meeting in 1923 

 in connection with the effect of polarised light on starch grains. 



The fact of the hydrolysis of starch and of other higher organic compounds affords 

 an explanation of many of the observed effects of moonlight and of some of the 

 so-called ' superstitions.' 



The significance in connection with agriculture, timber-felling, &c., is discussed. 



Dr. N. V. SiDGWiCK, F.R.S. — Chemical Linkage. 



Thursday, July 25. 



Prof. J. Smeath Thomas. — Germanium Imide. 



In the experimental work described here Dr. W. Pugh and W. W. Southwood 

 collaborated. 



In a previous communication the product of the interaction of ammonia with 

 germanium tetrachloride was described. It was given the formula GeCliONHj, and 

 it readily takes up ammonia under pressure, forming a liquid having the formula 

 GeCli6NH3. 



