[2] While in Naples, Clarke climbed Vesuvius on numerous occasions, to take guests to the summit and observe the state of activity of the volcano.

In 1799 he set out with John Marten Cripps on a tour through the continent of Europe, beginning with Norway and Sweden, whence they proceeded through the Russian Empire—including Ukraine and Crimea—to Constantinople, Rhodes, and afterwards to Egypt and Palestine.

After the capitulation of Alexandria, Clarke helped to secure for England a number of statues, sarcophagi, maps, manuscripts and other antiquities which had been collected by French savants in the city.

From Athens, the travellers proceeded by land to Constantinople, and after a short stay in that city directed their course homewards through Rumelia, Austria, Germany and France.

[2] Besides lecturing on mineralogy and discharging his clerical duties, made several discoveries in chemistry, principally by means of the gas blow-pipe, which he had brought to a high degree of perfection.

[7][9][11][12] Clarke also removed other marbles from Greece including a statue of Pan, a figure of Eros, a comic mask and various reliefs and funerary steles.