"Those four papers... are occupied with the discussion of the properties of , , and the gases evolved during the , putrefaction, and of vegetable and animal matters. They contain the first distinct exposition of the properties of hydrogen, and the first full account of those of carbonic acid, besides investigations into the combining proportion of the latter, and the properties of s. They recount also the first successful attempt to determine the differences in which characterise the gases, and suggest the probability of there being more kinds than one of inflammable air."