The physical properties of commercial glasses are controlled, in a large part, by controlling the chemistry of the raw material makeup of the batch. Thus, a precise chemical analysis of samples of the batch raw materials is critical to controlling glass production. It is self-evident that the raw material samples so analysed must be representative of the raw materials used, or errors may be introduced when calculating the batch. For these reasons, representative sampling of glass raw materials is an essential part of controlling glass production. To accomplish representative sampling, all parts of the lot of raw material to be sampled must be allowed equal probability of being collected in the sample increment. For this requirement it is necessary to sample from a falling stream of the material. A generalised procedure is outlined.
