Early Stephenson lamp with perforated holes in metal cylinder, approx., 1817(Dave Harker reported: date of manufacture: 1917). See file for details. Duplicate card. Purchased with the help of a Science Museum Grant. G1A/52/50. Made of brass and steel. Height: 280mm x Diameter of base: 81mm. Very very rare lamp possibly worth 20,000 pounds. Unfortuneatly, the main inner glass tube is broken and is held together with plastic. A brass hole is fit to the top. The other tin-p, , , , late sheath has a rolled over vertical seam and 13 rows of holes 16mm dia. Punded around its surface. At bottom of this sheath, therre is a brass screwed ring soldered in which the base scrass into. The bass base is bell bottomed and is 82mm dia. This base base 14 off ÂĽ "dia. holes olvilled around its circunference a copper vessel is fixed into this base which carries a ÂĽ " dia. burner., , , , This burner is adjusted by winr pricher through the base. Condition in 1999: broken inner glass, very rare/collectable lamp. Weight: 700gms. Top of copper burner has 2-rows of 1/32"dia. Holes drilled around to allow air to enter the lamp.