Léon Lalanne (1811-1892) was a polytechnician and civil engineer. He published this 136-page manual in 1851. He describes the "glass-wrapped slide rule" that he will have manufactured in order to reduce its price.
His fragility did not allow it to be very successful.
His slide rule was made of paper and cardboard protected by two glass plates. So one could print the scales instead of engraving them on wood,
which allowed to decrease its price. But the glass of that time was very fragile…
