In February 1845 he and a business associate, Edward Augustin King (d.1863), set out for England to secure British and French patents for the invention. King described construction and use of a lamp in September 1845, and British patent No. 10,919 was granted to King on November 4, 1845. The patent described two styles of lamp. In one, a platinum strip (or filament) was operated in a glass enclosure, but was not in a vacuum. In the second type, a carbon strip held between two clamps was enclosed in a vacuum in the space above a column of mercury, in an arrangement similar to a barometer. The mercury column was required because vacuum pumps of the time could not provide the high vacuum needed to operate a carbon emitter for a practical duration. The construction of Starr's carbon lamp allowed the strip to be replaced when it failed, making the lamp renewable.