The term "Vaseline Glass" is usually used as a synonym for Uranium Glass, a type of pale-green, or yellow green glass produced by firing with small amount of uranium oxide.
Here are a few examples from Ebay.
Here's an interesting article from the Press of Atlantic City
Question: The covered milk glass cream pitcher and sugar bowl shown in my photographs were purchased at a Delaware thrift shop. They are 5 inches high, approximately 5 ½ inches wide and in perfect condition. Both pieces are marked with the intertwined W and G that I have drawn. I would be interested in knowing who made the set as well as its value and age. - B. H., Port Republic
Answer: The logo you provided was used by the Westmoreland Glass Co. of Grapeville, Ohio. Founded as the Westmoreland Specialty Co. in 1889, the firm became the Westmoreland Glass Co. in 1924 and used the logo you drew from 1949 until 1984, when the factory closed.
Your lidded set's molds, featuring graceful swans nesting in bulrushes, were created by Westmoreland Specialty Co. at the turn of the last century. The pieces were part of a milk glass Swan line of table items that included covered celery vases, toothpick holders and salt cellars. A similar set with basket weave base was produced in blue milk glass.
Interest in milk glass was revived following WW II when Colonial-style architecture and interior décor were popular, and Westmoreland re-introduced the Swan line, hens-on-nests and other early milk glass objects that had enjoyed success. Known as Late Swan, your pieces are somewhat heavier and less opalescent than their early counterparts. However, a set with both lids intact will attract avid milk glass collectors who cheerfully pay $60 to $75 to own a perfect pair of Westmoreland swans.
And here are a few other milk glass swans to satisfy your collecting urges.
Here are a few of the better antique milk glass auctions currently taking place.
Pressed glass is a type of glass invented in 1825 by American inventor John Bakewell, who devised a way to press molten glass into molds, thus great increasing the rate at which glass objects could be produced.
Most milk glass of the late 19th and early 20th centuries was produced by this method.