"We find him... collecting the elastic fluids on which he experimented, with various precautions to secure their purity, observing carefully from how many different sources they could be procured with identical properties, and determining with numerical precision the relative volumes yielded by different processes. The questions of their permanent elasticity, their in different liquids, their combustibility or power to support combustion, their specific gravity, and likewise their combining equivalent, were all carefully enquired into."