The Hieronimus letter to Jellinek:
In 1903, Hieronimus worked for the Arnold Spitz Co. in Vienna, Austria. Spitz was one of the oldest automobile dealers in Vienna, Schlickgasse 3. Spitz was Benz, Mercedes, De Dion and Darracq agent. Moreover, the Spitz Co. assembled a handful Spitz touring cars powered by De Dion or Mercedes engines.
On Wednesday, 1 April 1903, Hieronimus started at the wheel of a Mercedes in the hillclimb from Nice up to La Turbie. The red-painted Mercedes was a 9.25-litre Sixty owned by Gerald Higginbotham of Ivyholme, Macclesfield, Cheshire, England. Hieronimus achieved fastest time of the day, 19 seconds ahead of Werner in another Sixty. (The race was stopped after the Zborowski accident.)
On Sunday, 24 May 1903, Hieronimus drove No. 36 Mercedes in the Paris-Madrid. The Mercedes was painted matt-white, a 12.7-litre Ninety owned by Richard von Stern of Vienna. Hieronimus arrived at Bordeaux on position 65 overall, position 32 in the 1000-kg class, more than four hours behind Gabriel's winning Mors. Warden's Sixty arrived on position 5 overall, Gastaud's Sixty on 8, then Jenatzy's Ninety on 14 and Max's Forty on 15.
Jellinek was upset and questioned Hieronimus' ability. In his letter to Jellinek dated 4 June 1903, Hieronimus explained that from the start at Versailles up to the first neutralisation at Rambouillet (26 kilometres) he could not drive at full speed as the road was crammed with spectators. Then, from Rambouillet via Ablis (the straight stretch of route nationale between Rambouillet and Ablis was part of the Paris-Madrid as well as of the Coupe de l'Auto course) to Chartres, Hieronimus made one of the field's fastest times. He completed the 47.5 kilometres from Rambouillet to Chartres in 22 min 15 sec. This was an average of 128 km/h, with standing start at Rambouillet, a sharp corner at Ablis, and a standing finish at Chartres. (Overall winner Gabriel's time in No. 168 Mors was 24 min 15 sec.) Then, beginning on the stretch from Chartres to Bonneval, Hieronimus' tyres began to overheat and regularly blew out.
Hieronimus in the 12.7-liter Mercedes before the start of the Paris-Madrid and after the arrival at Bordeaux,
from the Jules Beau collection, Bibliothèque Nationale, Paris: