 On the other hand, the mere existence of formulae would not suffice to make them geometrical in character. This need to give them a geometrical grounding was recognised by Lobachevskii in his earliest publications, but being in Russian they were not read outside Russia (nor were they appreciated by Russian mathematicians). He dropped his considerations of this kind in his pamphlet of 1840, upon which much of his reputation depends to this day, but brought them back in his last presentation, the Pangéométrie (1856), which, however, did no better than the earlier versions.