All Kidding aside, the style of engraving pictured is known as "Liberty" by the Italian engravers who innovated it. I have never been able to determine why Italians use an English word instead of the Italian libertà to describe that style but I have supposed that liberty is another way of saying freedom of expression.
Some English speaking engravers actually call Liberty engraving "spaghetti engraving."
Andrew has noted above the books where the Liberty style can be found.
Yes Roger you are right i'm italian and in italy this style is know in this way ,maybe because it came from the art nouveau style ,that in italy take the same name "liberty" and for example in Spain take the name "Modernismo" but all are the same ART NOUVEAU