The apparatus is filled by placing the lower end of the main tube under water, closing the tubes, f and i (with caoutchouc tubing and clips), and opening the stopcocks, a and d. Water is then sucked in from a, and the whole apparatus carefully filled. The cocks are then turned, and the cut end of the shoot fixed into i, as stated; care must be taken that no air remains under the cut end at i, and the end of the shoot must be at the level, k l. This done, the tube, f, may then be opened.
The leaves of the shoot transpire water, which is replaced through the stem at the cut end in i from the water in the apparatus. A bubble of air passes through the tube, f, and at once ascends into the graduated tube, a c. The descent of the water-level in this tube--which may conveniently be graduated to measure cubic millimeters--enables the experimenter at once to read off the amount of water employed in a given time.
It is not necessary to dwell on obvious modifications of these essentials, nor to speak of the slight difficulties of manipulation (especially with the tube, f). Of course the apparatus might be mounted in several ways; and excellent results for demonstration in class could be obtained by arranging the whole on one of the pans of a sensitive balance. H. MARSHALL WARD.
Botanical Laboratory, Owens College.
BOLIVIAN CINCHONA FORESTS.
The great progress made in the acclimation of cinchona trees in India, Ceylon, and elsewhere has awakened the governments of countries where the plants are indigenous to the necessity of conserving from reckless destruction, and replanting denuded forests, so as to be able to keep up the supply of this valuable product.
In Bolivia, since 1878, according to the report of the Netherlands Consul, private individuals and land owners have taken up the question with great earnestness, and at the present time on the banks of the Mapiri, in the department of La Paz, there are over a million of young trees growing.
New plantations have also sprung up in various other localities, either on private ground or that owned by Government. The competition of India and Ceylon in supplying the markets has had also the effect of inducing more care in collecting and also of revisiting old spots, often with the result of a rich harvest of bark which had been left on partly denuded trunks, and the opening up of new localities. The new shoots springing up from the old stumps have yielded much quill bark, and the root bark of the old stumps has also been utilized.