122 On the Formation, &c., of Carbohydrates in Monocotyledons. 



The quadrantal and semi-circular series of observations both gave 

 evidence of periodic vibrations of 115 seconds, but so small that they 

 could only be put down as giving superior limits, and not at all as 

 proving the existence of the couples. 



Assuming that the gravitation constant in the quadrantal case is G 

 for parallel and G' for crossed axes, the existence of a couple enables us 

 to find (G - G')/G, and the observations show that this fraction is not 

 greater than 1/16500. 



Assuming that the gravitation constant in the semi-circular case is G 

 for like parallel axes, and G' for unlike parallel axes, (G - G')/G is not 

 greater than 1/2850. The semi-circular vibration outstanding after 

 the elimination of disturbances was much greater than the quadrantal, 

 no doubt owing to the fact that want of axial symmetry would itself 

 lead to a semi-circular couple ; and though an attempt was made to 

 eliminate the effect, it was probably unsuccessful. 



" Contributions to our Knowledge of the Formation, Storage, and 

 Depletion of Carbohydrates in Monocotyledons." By JOHN 

 PARKIN, M.A., Trin. Coll., Camb. Communicated by Professor 

 MARSHALL WARD. Eeceived July 16, Eead November 17, 

 1898. 



(Abstract.) 



The paper is divided into two parts, the first dealing with the 

 formation of starch by assimilation in the leaves, the second with the 

 occurrence of starch and inulins in the reserve-organs of various 

 Monocotyledons. 



The author has investigated about seventy species, belonging to all 

 the principal groups of Monocotyledons, some of them at various 

 different stages of growth, and finds that starch due to normal assimi- 

 lation in the leaves occurs in very different amounts in different genera. 

 Relatively few produce much, and some form none at all, but species 

 from most of the principal families form some starch in their meso- 

 phyll. 



On comparing the type of leaf, its position and age, the habit of 

 the plant, and the period of normal activity, the author is led to 

 suggest that some connection exists with the storage or non-storage of 

 temporary starch. Broad and cauline leaves, those of aquatic Mono- 

 cotyledons, and those working at higher temperatures in the summer, 

 seem more prone to have starch than narrow radical leaves, those of 

 forms in dry situations, and those of spring species. That the age of 

 the leaf affects the question is shown by the results with Allium, a 

 genus long known not to form starch under ordinary conditions : the 



