for excess of gas, very little as a rule escapes into the room, and
consequently unpleasant smells are avoided.

This method of preparing sulphureted hydrogen will, I think, be found
useful in the laboratory. It is cleanly, much cheaper than the ordinary
method, and very convenient. During laboratory work, a burner is placed
under the retort and the sulphur kept hot, so that its temperature may
be quickly raised to the boiling-point when the gas is required. From
time to time it is necessary to replenish the retort with sulphur and to
remove the condensed portions from the neck.--_Chem. News_.

* * * * *

"SETTING" OF GYPSUM.--This setting is the result of two distinct, though
simultaneous, phenomena. On the one hand, portions of anhydrous calcium
sulphate, when moistened with water, dissolve as they are hydrated,
forming a supersaturated solution. On the other hand, this same solution
deposits crystals of the hydrated sulphate, gradually augment in bulk,
and unite together.--_H. Le Chatellier_.

* * * * *

[Continued from SUPPLEMENT No. 383, page 6118.]




MALARIA.

By JAMES H. SALISBURY, A.M., M.D.