M. VILMORIN’S RESEARCHES. 821 
decide certainly-—that at a later stage of growth the lower joints be- 
come poorer, or, at least, if the sap does not become poorer in quality, 
it is manifestly less abundant. 
The ripening of the seeds did not seem, at least in our climate, to 
diminish the yield of sugar; but as this does not happen with us until 
the extreme limits of the season, and as our plants have been contin- 
ually enriching themselves in proportion as their growth continues, 
the influence of the ripening in these phenomena cannot be determined. 
It is only in these countries where the plant can attain the maturity 
of its grains in a continuously warm season, that the matter can be 
definitely settled. According to the report addressed by M. de Beau- 
regard to the Chamber of Toulon, the ripening did not have with his 
plants an injurious effect, and he considered the seed and the sugar as 
two products which may be obtained conjointly ; then, again, accord- 
ing to Mr. Wray, the Zalu-Kaffirs are accustomed to break off, by 
a slight rapid movement, the tuft of their plants at the time it makes 
its appearance, and thus increase the saccharine quality of the stalks. 
This matter, however, is of no importance in France, where the ripen- 
ing does not ensue sufficiently early to prove at all unfavorable. 
The saltish taste of the very lowest knots has led me to think that, 
in some cases, the salts might accumulate in predominance; I have 
had the intention, but not the opportunity, to satisfy myself of this by 
incinerations. ‘The fact would be in conformity to analogies, and de- 
serves attention. Of no importance as to the manufacture of alcohol, 
it still would have very much in that of sugar. 
The ability to determine as to the richness in sugar of the juice, is 
quite limited when recourse is not had to a polarizing saccharometer, 
and, even with this instrument, inversion is absolutely necessary for 
the juice of the sorgho, which always contains a greater or less pro- 
portion of poorly made or uncrystallizable sugar. However, if this 
instrument cannot be made use of, a tolerably good approximation 
may be arrived at by the following process: After having determined 
the density of the sap as it passes from the press, it should be caused 
to ferment with care, and as completely as possible, at a temperature of 
25 to 30 degrees, by the use of a very small quantity of the yeast from 
beer ; the original volume, baving been previously marked by a guage, 
