In chemistry and mineralogy blowpipes have been used as scientific instruments for the analysis of small samples since about 1738, according to the accounts of Torbern Bergman. One Andreas Swab, a Swedish metallurgist and Counsellor of the College of Mines is credited with the first use of the blowpipe for 'pyrognostic operations', of which no record remains. The next person of eminence who used the blowpipe was Axel Fredrik Cronstedt, who put it to the purpose of the discrimination of minerals by means of fusible reagents. In 1770 an English translation of Cronstedt's work was made by Von Engestrom, annexed to which was a treatise on the blowpipe. Despite this opening, assay by blowpipe was for the time an occupation undertaken for the most part in Sweden. Bergman's use of the blowpipe outstripped all of his predecessors, and he widened its application from mineralogy to inorganic chemistry, giving rise to what may be regarded as a masterpiece of philosophical investigation, "De Tubo Ferruminatorio", published in Vienna in 1779 (and translated into English in 1788). Bergman's assistant, Johan Gottlieb Gahn, is credited with improving the design and application of the blowpipe. Gahn travelled with a portable blowpipe, applying it to every kind of chemical and mineralogical enquiry, such as proving the presence of copper in the ashes of vegetables. Gahn published a "Treatise on the Blowpipe", which was reprinted a number of times in contemporary chemistry textbooks. Jöns Jakob Berzelius worked with Gahn to ascertain in a systematic manner of the phenomena presented by different minerals when acted on by the blowpipe. He established, according to Griffin, the notion that the blowpipe was an instrument of "indispensable utility", and his published work, later translated into English, was regarded as one of the most useful books on practical chemistry extant.