In 1965, Brill launched another important innovation in glass analysis, the comparison of interlaboratory experiments in order to verify analytical results (Brill 1965). ‘Originally inspired by a plea from W E S Turner’, according to Freestone, Brill first mooted his idea at the VIIth International Congress on Glass, in Brussels (Brill 1965a, I. Freestone, pers. comm. 2009). It wasn’t until the VIIIth International Congress on Glass in 1968, however, that Brill fully launched his concept of an ‘analytical round robin’, having distributed a number of reference glasses to be tested in different laboratories using a range of current techniques including X-ray fluorescence and neutron activation analysis (1968, 49). When discussing his motive for the experiment, Brill aptly stated: The truth is that the chemical analysis of glasses is a difficult undertaking and still remains in some senses an art (1968, 49). By conducting the round robin experiment, Brill hoped the results gathered from different laboratories would help ‘correlate [...] earlier results’ and ‘calibrate future analyses in reference to one another’, as well as suggest which out of the analytical procedures used was the most accurate and effective (1968, 49). The results of the round robin were presented at the IXth International Congress on Glass in 1971, and showed that, as Brill suspected, there was poor agreement between certain identified elements, and therefore these might be ‘troublesome’ generally across analyses (1971, 97). These included calcium, aluminium, lead and barium, among others (Brill 1971). Aside from their correctional potential, the results, from 45 different laboratories in 15 countries, also provided an enormous data set from which, Brill suggested, the participants could ‘evaluate their own methods and procedures against the findings of other analysts’ (1971, 97). At the time, Brill could hardly have suspected that the data would go on to have such great import, but Croegaards generation of preferred glass compositions, from statistical analysis of the data, were used successfully by many people until Brills own reference guide was published in 1999 (I. Freestone, pers. comm., 2009).