The most important researches of this really remarkable experimenter had to do with the acids.

The ancient world had had no knowledge of any acid more powerful than acetic.

Geber, however, vastly increased the possibilities of chemical experiment by the discovery of sulphuric, nitric, and nitromuriatic acids.

He made use also of the processes of sublimation and filtration, and his works describe the water bath and the chemical oven.

Among the important chemicals which he first differentiated is oxide of mercury, and his studies of sulphur in its various compounds have peculiar interest.
In particular is this true of his observation that, tinder certain conditions of oxidation, the weight of a metal was lessened.
From the record of these studies in the fields of astronomy, physics, and chemistry, we turn to a somewhat extended survey of the Arabian advances in the field of medicine.
ARABIAN MEDICINE The influence of Arabian physicians rested chiefly upon their use of drugs rather than upon anatomical knowledge.