From Geneva the travellers went northward, by Lausanne, Vevay, Bern, Zürich, and Schaffhausen, across Baden and Würtemburg to Munich. After visiting this and other German towns, they crossed Tyrol southwards to Vicenza, halting in the neighbourhood of the Pietra Mala to collect the inflammable gas which there rises from the soil. They spent a day in Padua, and three days in Venice; and on by Bologna to Florence, where Davy completed his analysis of the gas collected at Pietra Mala. Early in November they were again in Rome. He writes once and again to his mother, while his anxiety about the Royal Institution makes him send inquiries to Abbott as to what is going to happen there, and to charge him, “if any change should occur in Albemarle Street,” not to forget his books which are lying there. “I prize them now more than ever.” To his former master, Riebau, he wrote from Rome as follows:-- Rome, Jan. 5th, 1815. HONOURED SIR, It is with very peculiar but very pleasing and indeed flattering sentiments that I commence a letter intended for you, for I esteem it as a high honour that you should not only allow but even wish me to write to you. During the whole of the short eight years that I was with you, Sir, and during the year or two that passed afterwards before I left England, I continually enjoyed your goodness and the effects of it; and it is gratifying to me in the highest degree to find that even absence has not impaired it, and that you are willing to give me the highest proof of (allow me to say) friendship that distance will admit. I have received both the letters that you have wrote to me, Sir, and consider them as far from being the least proofs of your goodwill and remembrance of me. Allow me to thank you humbly but sincerely for these and all other kindness, and I hope that at some future day an opportunity will occur when I can express more strongly my gratitude.