Prékopa Ágnes (szerk.): Ars Decorativa 30. (Budapest, 2016)
Kornélia HAJTÓ: Zsolnay Pyrogranite: Tradition and Fact
The figures show that the architectural ceramic items usually referred to as “Pyro- granite” are not by any standard “dense”. Their water absorbency ranges between 10% and 17%, and their appearance and texture display similar variability. Some authors regard dense ceramic as material with water absorbency of less than 5%; others put the mark at 2%18 or even 0.5%.19 The misunderstandings surrounding Pyrogran- ite seem to go all the way back to Vince Wartha. We might ask how an experimental chemist specializing in silicates could have confused the material of tiles with porous material developed for buildings. The same mistake was made by a contemporary of Zsolnay and Wartha, the chemist Lajos Petrik (1851-1932), who also had good connections with the company. Petrik studied in Graz and started teaching chemical engineering in the Állami Ipariskola (State Industrial School) in Budapest in 1880. He began his research into ceramics at about the same time, and his results were published in several technical journals.20 In 1885, together with Zsolnay’s brother-in-law, the geologist Jakab Mattya- sovszky, who worked for the Geological Institute, he wrote a comprehensive study entitled Full Catalogue of Flungarian Raw Materials for the Ceramics, Glass, Cement and Mineral Paint Industries, which was published by Mattyasovszky’s institute.21 This included descriptions of the clay deposits in Hungary and firing test results giving the refractoriness of the clays. “Since the Geological Institute did not have the means to carry out firing tests in its laboratory, Mr Lajos Petrik, teacher of the State Industrial School in Budapest, having charge of a laboratory excellently equipped for such purposes, kindly and readily undertook this major task. ”22 Thus in addition to his geological prospecting work, which involved determining the chemical composition of potential industrial raw materials, Petrik conducted laboratory experiments on the firing of clay of various compositions. In an 1897 article on the ceramics industry,23 he wrote: 127 Zsolnay paving brick, salt-glazed high-fired brick, fired between 1200 and 1250°C, chamotte clay,17 first third of 20th century? 2069 7. 03 % Bigot architectural ceramic, France, 1899-1900 2040 6.2 %
