Commander A. S. Mackenzie having applied December 16th for the second in command, the Naval Commissioners asked Perry in regard to the number and arrangements of the crew of the _Missouri_. He recommended that there should be on each of the large steamers a captain, and a commander; so that, after some experience, the latter could take command of the medium or smaller steamers to be hereafter built. From the first Perry urged that all our naval officers should learn engineering as well as seamanship, so as not to be at the mercy of their engineers. In the beginning, from the habits, education, and manners of engineers taken from land or the merchant service, one must not look for those official proprieties derivable only from a long course of education and discipline in the navy. Hence there would be a natural disposition to exercise more authority than belonged to them, and to be chary of communicating the little knowledge they possessed. A purely naval officer in such condition would be like a lieutenant at the mercy of the boatswain. The captain must not carry sail without reference to the engines, and so the steam power must not be exerted when mast, spars or sails would be strained. Harmony between quarter-deck and engine-room was absolutely necessary. The British Government encouraged officers to take charge of private steamers so as to acquire experience, and no man unused to the nature of machinery could command a British war steamer. In our navy no one should be appointed to command in sea steamers unless he had a decided inclination to acquire the experience. Even while the _Missouri_ was building, Perry wrote a letter concerning her complement, and after speaking a good word for the coal heavers and firemen, and praying that their number might be increased, he again proposed a scheme for the supply of naval apprentices for steamers. He suggested also that a class of Third Assistant Engineer should be formed. This would create emulation and an _esprit du corps_ highly favorable for high professional character and abilities among the engineers. The grade would be good as a probationary position, besides reducing to a minimum, jeopardy to the ship and crew. In a word, Perry foresaw that, if the splendid new steam frigate _Missouri_ were left to incompetent hands, she would fall a prey by fire or wreck, to carelessness and ignorance. “He was proud of these two vessels, and no one had a better right to be proud of them than he. He imagined them and created them, while others did the details and claimed most of the credit of their superiority over men-of-war of that day of other nations;” for down to 1850, our policy was to build better vessels than were built in any part of the world. Thus our navy was small but very effective.