14 



NATURE 



[September 4, 1919 



had hitherto, he pointed out, been Hmited to the 

 fundamental standards of mass and length and ques- 

 tions intimately connected with these. M. Battistella 

 urged that this was insufficient to secure uniformity 

 in all the details of importance to international science. 

 In the name of his Government he directed attention 

 to (i) the necessity for a legal definition, not only of 

 the fundamental units of mass and length, but also 

 of a whole series of connected units — units dealt with 

 in the study of light, heat, engineering, and elec- 

 trical problems, and others, as well as for the speci- 

 fication of the instruments best suited for the 

 measurement of these quantities; and (2) the im- 

 portance of the standardisation of the types of instru- 

 ments to be employed so as to secure uniformity 

 among countries using the metric system. As a 

 result the International Committee was entrusted 

 with the mandate of examining the proposal of the 

 Italian delegate with the view of securing agreement 

 on the questions raised. 



Enough has, perhaps, been written to show that 

 the matters under discussion were of no small import- 

 ance. None of them were settled; it remains for a 

 future conference to examine them afresh and to 

 decide each in the manner which promises best to 

 be of service to the world and to turn to advantage 

 the lessons of the past five years of trial. 



.'\nd now there is no space to describe the other 

 half of the volume : M. P^rard's elaborate note on 

 the reduction of certain classes of observation or 

 M. Chappuis's two papers on the determination of 

 the boihng.point of sulphur and the coefficient of 

 dilatation of mercury. It must suffice to mention 

 the results. For the boiling-point of sulphur on the 

 thermodynamic scale under norma! oressure he finds 

 the value 44460°. Holborn and" Henning give 

 44451°. and Day and Sosman 444-55°. The value at 

 present in use at the National Phvsical Laboratory is 

 444-5°- 



For the coefficient of dilatation of mercury his value 

 is o-i8i62884x io-= + 8-5962282 X 10- 'T. This value 

 does not differ greatly from that deduced from bis 

 own earlier experiments of 1890; the differences 

 between these results and those of Callendar and 

 Moss (Phil. Trans., 191 1) are oonsiderablv greater. 

 For the range from 60° to 100°, where Chappuis's 

 two results agree very closelv, the difference between 

 them and the figures of Callendar and Moss would 

 correspond with a temperature error of 0-25°, an error 

 ten times greater than that which M. Chappuis con- 

 siders possible. 



M. Chappuis died as the proofs of his paper were 

 passing through the press. Those who' know his 

 work will wish to join in M. Guillaume's tribute to 

 his memorv. He w-rites : — "These two determina- 

 tions of the coefficient of dilatation of mercury, 

 separated by a quarter of a century, carried out by 

 methods entirely different and with instruments 

 which had no part in common, and yet in close 

 agreement, will remain for metrologists of the future 

 among the finest examples of the work of an experi- 

 menter gifted with consummate skill, with a devo- 

 tion to his_ task which stood every test and with an 

 intense desire to reach the truth."' R. T. G. 



SOME INDIAN SUGAR-CANES AND 

 THEIR ORIGIN. 



T~\R. C. A. B.'VRBER, Government Sugar-Cahe 

 -L^ Expert, Madras, continuing his studies on 

 Indian sugar-canes, has given an account of the 

 classification of two new groups which he describes 

 as .Saretha and Sunnabile (Memoirs of the Depart- 

 NO. 2601, VOL. 104] 



ment of Agriculture in India, Botanical Series ix.. 

 No. 4). In the course of study of the Indian canes 

 a sharp distinction was observed between two classes. 

 There was, on one hand, a large series of thick, juicy 

 canes commonly grown on a crop-scale in the more 

 tropical parts, or in the northern parts usually in 

 small plots under high cultivation near large 

 towns, in which they were used for eating as 

 fruit. A second series of thin, hardy canes, 

 grown under field conditions all over India, 

 especially in the north, were unfitted for chewing, but 

 were crushed and made into "jaggery" or "gur." It 

 is this second series which includes the subject of 

 the memoir. In contrast with the first series these 

 thin canes are considered to be indigenous to India, 

 and were found to include several well-defined classes. 

 A number of apparently isolated forms from all parts 

 of the country were at first difficult of arrangement, 

 but were^ afterwards found to fall into two groups, 

 characterised by bending or erect leaf-tips and presence 

 or absence of circlets of hairs at the nodes; the canes 

 known as Saretha and Sunnabile have been selected 

 to give names to the new groups. In classifying 

 varieties under these two groups the characters usually 

 employed in systematic work, such as differences in 

 the floral organs and size of organs and plants, have 

 not been found helpful, but dependence has been 

 placed on a series of minute local differences. Thus 

 in all the Saretha group there is a minute incrusta- 

 tion on the rind, as if it had been attacked by a small 

 mite, whereas this iss absent in the Sunnabile group. 

 The density of bloom is greater in the Saretha group, 

 but the blackening of this bloom by fungus is sharper 

 and more circumscribed in the Sunnabile group. 

 Thickness of stein and size and vigour of plant seem 

 to be of no value ; and the existence of insignificant 

 characters in canes differing considerably in external 

 appearance, and extending through wide stretches of 

 country under varying climatic and cultural condi- 

 tions, adds to their importance. Some sixtv to seventy 

 such characters are dealt with in detail. 



Dr. Barber further points out that his classification 

 is. not merely an empirical statement of unconnected 

 differences, a sort of analytical key for the separation 

 of varieties, but also presents data for a statement on 

 the- lines of evolution among a section of cultivated 

 canes. He claims to have advanced towards solving the 

 origin of cultivated canes from their wild ancestor, 

 and to have established a series of connecting links 

 between cultivated canes and the wild species of 

 Saccharum now growing in India. A wide collection 

 of specimens shows that there are some verv distinct 

 varieties of Saccharum spontaneutn more or less con- 

 fined to definite geographical regions. A development 

 in the size of the vegetative organs is observed in 

 passing from the dry to the humid tracts in India 

 similar to that met with in the Saretha and Sunnabile 

 series of sugar-canes, and in the detailed list of 

 characters showing differences between the two 

 groups we find a number nientioned in which the 

 Saretha group approaches S. spontaneum. Such are 

 the black incrustation on the stem, the circlet of hairs 

 on the nodes, and certain leaf-characters, and these 

 resemblances suggest that the Saretha group is the 

 more primitive. But as a study of the seedlings of 

 S. spontaneum raised at Coimbatore shows differ- 

 ences among themselves similar to those obtaining 

 between the two groups, it is considered that the 

 Sunnabile varieties are also traceable to the same 

 wild species. 



Dr. Barber describes a method for building up an 

 ideal cane for each variety and group. The results 

 have been reduced to curves, which show the differ, 

 ences sufficiently well, but involve considerable labour, 

 as in some cases thev are based on as manv as 



