(London, Richard Taylor, 1828). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1828 - Part I. Pp. 105-112.
First appearance of the paper in which Barlow described his invention of the so-called first ""Barlow-Lens"".He constructed his first achromatic telescope lens by enclosing liquid carbon disulfide between two pieces of glass. The Barlow- lens has come into general use for increasing the eyepiece power of any optical instrument.