IAN SIMMONDS

Subtle differences between the centers of two miniature drawer pulls reveal how a mold maker solved a tricky problem — creating a mold with a fixed volume, to be filled with varying quantities of glass.

Pressed glass knobs play a special role in glass history.

It took American inventors over thirty years to advance glass pressing to the point where it was capable of this. At 9 inches tall and 7½ inches in diameter, and made by the New England Glass Company circa 1869, it is the largest pitcher pressed before 1880.

Why did it take so long?

A simple 7 1/2" tall chestnut-shaped blown bottle shows that an object's glass itself can make the object stand out from the crowd.

Little more than elongated bubbles slightly flattened into a characteristic chestnut shape and with an applied string lip, bottles such as this were a staple of bottle manufacturers in America from the late 18th Century until mold forming took over in the 1820s and 1830s. The form continued to be made as glassblowers moved west to the new lands of Western Pennsylvania and northern Ohio.

The tightly sealed, hollow stem of a small cream jug presents collectors from two different fields with quite a problem — no less than a coinundrum

Trapped within is a rare, nearly uncirculated 1831 United States five cent coin, known to collectors as a "capped bust half dime."

An odd looking sugar bowl, bearing a distant family resemblance to the rare mold blown masterpieces of 1820s New England, was a welcome substitute for collectors of lesser means in the 1930s, and was put onto the market for that very purpose.

However, the same cannot be said for this bowl:

A stork stands on a rocky shore, surrounded by tall grasses and grasping a favorite delicacy in its beak — a small, still writhing snake. An extraordinarily rich red shading down to yellow amber sets a mood of evening, of a brilliant sunset.

Long considered one of the most desirable forms among collectors of American art glass, this vase is all the more remarkable because it was machine pressed, in a mold. But why?

As rare as hen's teeth, this 5 1/4" high amber Ohio flask has a pattern known to collectors as "popcorn."

Blowers got considerable mileage from an ancient tool — a small, cup-shaped mold surrounded by deep vertical grooves.

A green and green amber flask with scroll borders shows that bottle makers considered it more than reasonable to advertise themselves prominently on their products.

This particular flask announces that it was made at the Louisville Glass Works, in Louisville, Kentucky, which operated between 1855 and 1874 in a factory opened in 1850 by the Kentucky Glass Works.

The fashionable heart and lyre border and wide field of strawberry diamonds conceal the experimental nature of this rare example of early American pressing.

Machine pressing was America's first great contribution to glass technology, providing a radical new method for shaping and decorating glass. In the process it gradually reduced the role of blowers and cutters in the design and decoration of glass, transfering skill and design to a small and influential group of designers and mold makers. It laid the foundation for today's glass industry in which the vast majority of products are mass produced and inexpensive yet decorative.

A pair of finger bowls made and decorated in New York City in the 1850s or 1860s help clear up a lingering question about the removal or modification of engraved decoration.

The curator's question was simple: "Could that monogram have been added on top of another?"