In The Analysis of Matter (1927) Bertrand Russell constructs point-instants from

events. During the writing of the manuscript, he encountered a problem with

the initial definition of a point-instant and revised the definition accordingly in

the published version. My principal aim is to show that the problem was

brought to his attention by F.P. Ramsey. Secondly, I explain the reason why

Russell investigates, and consequently endorses, a different method of construction

of point-instants in Human Knowledge (1948), even though he was able

to overcome the difficulties involving the construction of point-instants in The Analysis of Matter.