correspond to a richness of 8 thousandths of CO_{2}; and 5½ to 3.6
thousandths. This half-bulb serves likewise for another purpose. From the
moment that the large bulb makes the lime-water turbid with an air
containing two per cent. of CO_{2}, it is clear that the small one can
cause the same turbidity only with air twice richer in CO_{2}, _i.e._, of
four per cent.

This apparatus, although it makes no pretensions to extreme accuracy, is
capable of giving valuable information. The table that accompanies it is
arranged for a temperature of 17° and a pressure of 740 mm. But different
meteorological conditions do not materially alter the results. Thus, with
10° less it would require thirty-one injections instead of thirty, and
CO_{2} would be 0.64 per 1,000 instead of 0.66; and with 10° more, thirty
injections instead of thirty one.

The apparatus is contained in a box that likewise holds a bottle of
lime-water sufficient for a dozen analyses, the table of proportions of
CO_{2}, and the apparatus for cleaning the tubes. The entire affair is
small enough to be carried in the pocket.--_J. Arnould, in Science et
Nature_.

* * * * *

[NATURE.]




THE VOYAGE OF THE VETTOR PISANI.