A gather of glass is the volume of molten glass needed to be drawn from the pot in the furnace by the glassblower, to work into the preliminary shape. Often more glass is needed to add handles, stems or embellishments.
We have imperial and metric units to measure solids and liquids, weights and volumes can then be related to value, and this is the basis of commerce and our economy.
Metrication is the international decimal system of weights and measures, based on the metre for length and the kilogram for mass, that was adopted in France in 1795 and is now used officially in almost all countries. The Kilo (kg) and the metre (m) replaces such ancient imperial values such as barleycorn, hand, chain, perch, furlong, fathom, fluid ounce, gill, quart and gallon.
Glassmaking in an industrial environment needed a system of controlling the amount and cost of material used, to make a set number of products, allowing their value to be calculated and accounted for. The molten glass or metal was drawn from a pot or crucible which had been charged with 15-18 cwt of dry ingredients.
Cwt is an imperial measurement of 1 hundredweight and equals 50.8 kg, therefore 15-18 cwt equals 0.75-0.9 metric tonnes.
From that volume of metal, it was possible to calculate the number of pieces (eg tumblers) that could be made. The size and shape of each piece worked was fundamental to the skill of the glassmaker, they were making ‘sets’ of tableware so the pieces had to match. The team or chair would earn a set sum from that pot of metal over the course of their shifts, called journeys, from the French journée, meaning a day. This was the basis of piecework; being paid for the number of pieces you produce.
Allowances were made for some waste material from trimmings or breakages but if too much metal was gathered from the pot then there would not be sufficient metal left in the pot to complete their target earnings. Waste metal could not be put back into the pot until it had been cooled, cleaned, and broken up for cullet to be added to the next batch.
The amount of metal required for each piece is known by glassmakers, it is not defined as a specific weight or volume. To an onlooker it would not just be difficult to gauge, but also to communicate. So how do glassmakers measure and communicate, and what units of measurement do they use?
Explaining the terms used by glass-makers, to quantify the amount of molten glass, they needed to take for each piece of work. The volume differed with each piece, not quantifiable but they all knew how much they meant.