Airy (George Biddell) Autograph letter signed ('G.B. Airy') to Professor Volpicelli in Rome, recommending 'to your kind attention Mr John Fowler, one of our most distinguished engineers. This letter will be delivered to you by that gentleman; if you are able to render him any service, I shall be greatly obliged', one page, address leaf, folding marks, small loss to paper due to seal removal, 8vo, Royal Observatory, Greenwich, 20 November 1866.  ***Sir George Biddell Airy (1801- 92) was Astronomer Royal from 1835 to 1881. His many achievements include work on planetary orbits, measuring the mean density of the Earth, a method of solution of two-dimensional problems in solid mechanics and, in his role as Astronomer Royal, establishing Greenwich as the location of the prime meridian.