Source: John Swan, Speculum Mundi, published in 1635
This is an example of a wire watermark, depicting a portion of one of at least three different watermarks that were used by the printer of this book. Looking at this image by itself, it is not easily identified. But, as can be seen in the image below, by combining numerous portions of the same watermark together, we can identify a vase with two "S"-shaped handles holding an arrangement of stylistic flowers. On the front of the vase are the letters "R" and "P".
Additional Book Information
Speculum Mundi Or A Glasse Representing The Face Of The World, Shewing Both That It Did Begin, And Must Also End: The Manner How, And Time When, Being Largely Examined. Whereunto is joyned an Hexameron, or a serious discourse of the causes, continuance, and qualities of things in Nature; occasioned as matter pertinent to the work done in the six days of the Worlds creation. Aug, in Ser. de Ascen. Qui Se dicit scire quod nescit, temerarius est. Qui se negat scire quod scit, ingratus est. (Published at) Printed by the Printers to the Universitie of Cambridge. 1st Edition. 1635