Complex sentence: Both men attended the 1851 Great Exhibition in London, where the exhibition on photography greatly influenced Glaisher: he called it "the most remarkable discovery of modern times," and argued in his official report for using microphotography to preserve documents.
Split into simpler sentences: Both men attended the 1851 Great Exhibition in London, where the exhibition on photography greatly influenced Glaisher. He called it "the most remarkable discovery of modern times," and argued in his official report for using microphotography to preserve documents.