Chief engineers of river steamers. First assistant engineers. Second assistant engineers. Third assistant engineers. Special engineers. All steamers of over one hundred tons burden shall carry at least one chief engineer. First assistant engineers may act as first assistants on any steamer. Second assistant engineers may act as first assistants on steamers of seven hundred and fifty tons and under, and second assistants on any steamer. Third assistants may act as second assistants on steamers of 750 tons and under, and third assistants on any steamer. Special engineers may be assigned to act in any capacity for which they are qualified on steamers of one hundred tons and under. Inspectors may designate upon the certificate of any chief engineer the tonnage of the vessel on which he may act, and they may also designate any assistant engineer as special engineer on steamers of one hundred tons or under, and may restrict an engineer to a particular vessel. 3. Engineers on high pressure steamers navigating rivers shall be designated as chief engineers (H. P.), assistant engineers (H. P.), and special engineers (H. P.). Assistant engineers may act as chief engineers on high-pressure steamers of one hundred tons burden and under, of the class and tonnage, or particular steamer, for which the inspectors, after a thorough examination, may find them qualified. In all cases where an assistant engineer is permitted to act as first [chief] engineer, the inspector shall state on the face of his certificate of license the class and tonnage of steamers, or the particular steamer, on which he may so act. 4. It shall be the duty of an engineer, when he assumes charge of the boilers and machinery of a steamer, to forthwith thoroughly examine the same, and if he finds any part thereof in bad condition, caused by neglect or inattention on the part of his predecessor, he shall immediately report the facts to the local inspectors of the district, who shall thereupon investigate the matter, and if the former engineer has been culpably derelict of duty, they shall suspend or revoke his license. 5. No original license shall be issued to any person to act as engineer, except for special license on small pleasure steamers, who cannot read and write, or who has not served at least three years in the engineer's department of a steam-vessel, or as a regular machinist in a machine works; provided that any person who has served for a period of three years as a locomotive or a stationary engineer may be licensed to act as engineer on steam vessels after having had not less than one year's experience in the engineer's department of a steam vessel. CHANGES IN STEAMBOAT RULES. Amendments Made by the Supervising In- Section 5, rule 5, has been amended so that no person shall receive an original license as engineer who has not served at least three years in the engineer's department of a steam vessel, except locomotive and stationary engineers, and a regular steam engine machinist; and no person shall receive a license who is not able to determine the weight necessary to be placed on the lever of a safety-valve to withstand any given pressure of steam in a boiler. By section 18 the grade of an engineer or pilot shall not be raised during the term for which the license was granted, except by consent of the board that granted the license. IT being agreed that heat is the agent which does work in an engine, and that steam, air, and vapor are but the instruments for transmitting the motion of heat to the machinery, our object will be to store up in an elastic working substance the heat derived from fuel, and to guard against loss as far as possible. As a general rule chemical combination is accompanied by the evolution or production of heat, and chemical decomposition by the disappearance of heat equal in amount to that produced during the previous combination of the elements which are undergoing separation. Combustion, or burning, is the name given to rapid chemical combination attended with the evolution of intense heat. It is necessary to bear these facts in mind in estimating the heating effect of fuel. Thus, where hydrogen and oxygen exist in coal in the proportion necessary for forming water (viz: one of hydrogen to eight of oxygen by weight,) it is usual to assume that they do not influence the heat of combustion. * Goodeve. The hydrogen is taken to have been already burnt in oxygen. In coal there may be 5 per cent. of hydrogen, and 4 per cent. of oxygen: this would leave 41⁄2 per cent. of hydrogen available for heating purposes. There appear to be exceptions to the above rule, and Dr. Percy gives the result of an experiment where two coals closely agreeing in ultimate composition have been found to differ by 5 per cent. in heating power. The composition of various kinds of coal is given by Dr. Percy, in his work on fuel, and it is well known that the differences in the constituent parts of coal are very great, and give rise to qualities of various kinds which influence the selection to be made for heating purposes. The heat given out in the burning of hydrogen and carbon is estimated as follows: I pound of hydrogen consumes about 36 I pound of carbon burnt to carbonic oxide, Units of Heat. 62,032. 4,452. 14,545. According to Dr. Percy the heating power of a substance is the number of units of heat produced by the combustion of a unit of weight of the substance; and if the unit of heat be defined according to the Centigrade scale Heating power of hydrogen is 34,462. |