11 



the different coloured rays in succession. Plants, however, do not 

 assimilate all the oxygen of the carbonic acid and water, and some 

 of it escapes, and thus the air we breathe is purified. 



Starch is formed in the leaves, and is conveyed, when produced, 

 to other parts of the plant — to the tuber of the potato-plant, for 

 example. But starch is insoluble in water : how then can it pass 

 through the cell-walls of the plant and into the circalation ? This 

 effect was shown to be brought about by the agency of such 

 substances as "malt extract," which is present in all plants, and 

 which renders the starch soluble, though it is then no longer starch 

 but a substance closely allied. Thus dissolved, it passes along the 

 vessels, and in the tuber of the potato-plant, by a process yet 

 unknown, is once more converted into starch. 



MAY 6th. 



Mr. John Knox Laughton, E.N., M.A., F.E.A.S., F.M.S., 

 Mathematical and Naval Instructor, Royal Naval College, Green- 

 wich, read a Paper on "Weather Forecasting : " — 



Probably no subject is of such general interest as the Weather, 

 but as yet much of our knowledge regarding it is no better than 

 empirical. Of folk-lore some is really valuable, but the rest is 

 curious nonsense. The predictions founded upon changes of the 

 moon, the moon's crossing the equator (Mr. Saxby's idea), the old 

 moon in the new moon's arms, &c., may have some germ of truth in 

 them, though it is difficult to find it ; but it is simply absurd to 

 connect weather fluctuations with changes of the moon which take 

 place on a Saturday, Sunday, or Monday. Weather may be 

 influenced by the position of the planets, but of this we as yet 

 know nothing. Mr. Meldrum, of Mauritius, believes that he has 

 discovered a connexion between atmospheric changes and those 

 disturbances on the face of the sun known as " sun-spots." 



Passing to the indications afforded by clouds we come to a more 

 scientific basis, of which the value is not likely to be underrated. 

 Much of the modern science of meteorology depends upon the study 

 of clouds. Thus Cirnit; (mares' tails) shows the direction of the 



