A scientist's reputation long after his death depends not only on his achievement but also on a number of other factors. The relation of his work to later research obviously affects his posthumous influence. Gay-Lussac's law of combining volumes of gases was of great importance to nineteenth-century chemistry, although in the twentieth century it is likely to be mentioned only in an elementary exposition of the subject. The law of thermal expansion of gases is today more commonly associated with the name of Charles than that of Gay-Lussac. Posthumous fame so often depends on the practice of eponymy, misleading though it may be. A teacher's name tends to be kept alive by his students and we shall have to consider to what extent Gay-Lussac influenced students at the research level. The author of a text-book inevitably influences a wide circle of students but we have seen that the only text-books published under Gay-Lussac's name were extracts from lecture courses, compilations of which he disapproved.

After Gay-Lussac's death anyone who wished to consider his work would have to extract it for the most part from the appropriate journals, a method of publication more likely to bury than display any achievement.