William Kennish (born 1799, in Maughold, Isle of Man, died, March 19, 1862 in New York City), was a poet, engineer, explorer, scientist, inventor, and the first person hired by the United States government to explore a route for a Panama Canal.
He was born in the Parish of Maughold, on the Isle of Man, in a cottage on the Douglas-Ramsey Road. He spoke Manx, and knew very little English until he became a seaman in the Royal Navy at the age of 22. He learned English and rose to the rank of Master Carpenter by the time he was 27. In October 1826, he married Mary Byford, of Gillingham, Chatham, Kent, England.
Between 1827 and 1832, while in the service of the Royal Navy, he invented a system for correcting pointing naval artillery for parallax and a system for moving naval artillery on to land and using it there. He improved the design of the theodolite. He introduced the practice of painting naval vessels gray. In addition, he worked on an artificial horizon for navigation; a[n] Automatic sounding instrument; a method of drowning the magazine of a ship of war ; an hydraulic ventilator; [and] a hydrostatic diving machine[.]" 
He retired from the Royal Navy in about 1840, and began writing poetry. In 1844 his collection of poems, Mona's Isle and Other Poems, was published in London. In 1845 he began teaching. Also about this time, he invented a system for a pneumatic tube to convey messages, which became commonly used after he died.
In 1849, he emigrated to America. He soon began surveying gold-bearing land in Columbia, and in 1855 planned a route for a Panama Canal for the United States government. His report on the survey of the Panama Canal was included in The Practicality and Importance of a Ship Canal to Connect the Atlantic and Pacific Oceans, published in 1855 by George F. Nesbitt & Co. of New York.