 In his earlier work, such as  The Principles of Mathematics, from 1903, Russell followed Peano’s practice of indicating conjunction by simply juxtaposing formulas. Thus the conjunction of \(p\) and \(q \) was written \(p q \). Russell began to use the punctuation dot for conjunction by 1905. The use of dots for punctuation in logic is now only of historical interest, although some textbooks use a raised dot \(p \cdot q \) for conjunction. Below we will explain the dual use of dots for punctuation and conjunction in PM.