90 
POPULAR SCIENCE REYIEW. 
campestris) radiated from a central point in a manner whicli he thought 
had not been recorded by other observers. As usually seen, the mushroom 
seemed to rise from various points along the mycelium, or underground 
thread, without any regular order or system. Fungi, like flowering plants, 
had other modes of propagation besides seeds. As in the potato, we had 
one system elevating its parts into the atmosphere ending in seeds, and 
another sending thready stolons under ground terminating in distended 
stems or tubers — the threads dying away after the tubers were mature — so 
in the common agarics we have the parts known as the “ mushroom ” which 
elevates itself into the atmosphere, and produces reproductive bodies like 
seeds called spores ; and we also have underground white threads starting 
out from the base of the mushroom which at their terminus bear buds 
which next year become mushrooms, as the swollen ends or tubers of the 
potato produce plants. The observations which he supposed new referred 
to the distance which the spawn-threads traversed in one season, and the 
regular manner in which the mushrooms appeared from the parent of the 
past year. 
The Compositce of Bengal. — Mr. C. B. Clarke recently (November 21) 
read a paper on this subject before the Linnean Society. The author cor- 
roborated Mr. Bentham’s estimate of the very small proportion of Compositce 
relatively to the whole flora of flowering plants in the Indian peninsula as 
compared with other countries. In Bengal they show only the proportion 
of about one in twenty-two, and in Malacca the still smaller proportion of 
one in about forty-flve species. The number of Indian species of Compositce 
in De Candolle’s Prodomus ” will probably have to be considerably 
reduced. 
CHEMISTRY. 
Is or is not Water an Blectrolyte ? — M. Bourgoin, who has recently in- 
vestigated this subject, says that water is not an electrolyte, notwithstand- 
ing that current opinion is to the opposite effect (Bull. Soc. Chimique II., 
xvii. 244). His apparatus consists of a cell, divided into two equal com- 
partments by an impermeable septum, which septum is pierced with an 
opening so minute as to prevent any mixing of the liquids on its two sides, 
while yet it allows the passage of the current. The cell is so arranged that 
the gases evolved from the electrodes may be collected and measured. Both 
compartments are filled with water acidulated with sulphuric acid, and the 
currrent is passed for a given time, the hydrogen being collected. When 
the experiment is concluded, the contents of the compartments are sepa- 
rately analysed. Under these circumstances it is found that, in the positive 
compartment, the acid has increased in amount by a certain quantity er, 
while in the negative it has diminished by the same amount. The quantity 
of sulphuric acid decomposed is equal to 2a. But this quantity of acid can 
furnish only a third of the hydrogen obtained ; or, calling P the weight of 
the hydrogen measured, the acid can yield a quantity of hydrogen equal to 
It is therefore certain that it is not H 2 SO 4 which is decomposed, but 
O 
H 2 SO 4 + (H 20 ) 2 , or HgSOg. Two hypotheses may be offered to explain this 
