334 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Juke, 



TABLE NO. 2. 

 Expences of maintenance per annum of each kind of vessel. 



'Ihe expense of fuel is calculated at the rate of 24s. per ton, and the con- 

 sumption 9 lbs. (4 kilogrammes) per h. p. per hour, the number of days 

 steam up being 1 in 5. 



TABLE NO. 3. 



Sailing vessels. 



r 1 first rate 

 3 liners J. 1 second ditto 

 [l third ditto 

 22 frigates 1st class 

 5 20-gun brigs 

 5 gun boats 

 7 cutters, &c. 

 15 ... 



13 corvettes for transports 

 1 school ship 

 Batimens de servitude 



71 — The expense of maintenance of 71 sailing vessels 



on the plan .... 



Total allowed in budget of 1845 for sailing vessels 



Difference less on the plan 

 STEAMERS. 



Pay and Provisions. 



839,019 fr. 



068,267 



544,383 

 9,214,392 



517,453 



272,510 



414,512 



607,453 

 4,658,455 



199,310 



282,053 



15,219,107 

 18,553,616 



3,334,509 fr. 



5 of 450 h. p.] 

 5 of 320 y Escadre. 



10 of 220 J 



1 of 450 1 



4 of 220 )■ Missions. 



5 of 160 J 

 20 of 160 Algiers 

 10 of 120 Service of ports and colonies 



60 — Maintenance of 00 steamers on the plan 

 Total allowed in the budget of 1845 for steamers 



Pay, Provisions, and Fuel. 



1,788,440 fr. 



1,181,815 



1,473,446 

 357,688 

 589,376 

 540,486 



2,161,954 

 823,360 



Note. The 1 

 15 flotilla boats 



Difference more on the plan 

 gun-boats, &c.,on the plan, will cost 



Together 

 For the same expense 18 steamers might be kept 

 8 of 120 h. p. 

 10 of 80 



up. 



8,916,565 

 5,516,612 



3,399,953 fr. 



087,122fr. 

 607,453 



1,294,575 



658,688 fr. 

 625,050 



Together . . 1,283,738 



The cost of the 10 steamers of 80 h. p. has been calculated with crews 

 of 40 men. 



TABLE NO. 4. 

 Extracts from the Navy Estimates (England) for 1844-45. 

 Funds voted specially for Steamers. 

 Coal for steamers .... 

 Purchase of engines and repairs 

 Building iron steamers 



Building wooden steamers, mixed up with the votes 

 for the rest of the tleet 



Woolwich. — Repairs of steam engines, construction 

 of boilers, enlargement of the repairing factory, re- 

 pairing dock for steamers, wages of men in the steam 

 factory ..... 

 Portsmouth. — New dock for steamers . 

 Plymouth. — Ditto .... 

 Malta. — New basin ; quay and coal depot 

 Allowances and grants to companies for mail service 



i:i09,559 



230,000 



36,623 



[677,783] 



80,000 

 30,000 

 30,000 

 17,000 

 432,541 



Total 



de937,047 



PROFESSOR FARADAY ON HEAT. 



A course of four Lectures delivered at the Royal Institute. 



Lectore I., April 20, 1844. 



(Specially reported for this Journal.) 



The Professor commenced his lecture by remarking that he did not know 

 which was the more delightful occupation, to receive and apply the laws of 

 science as divulged by others, or by well-devised and carefully executed inves- 

 tigations to assist in searching out those immutable laws by which the uni- 

 verse is governed. It was the object of the present short course of lectures to 

 consider the principal phenomena and general nature of that power commonly 

 called heat; and although there has been but little that is new brought for- 

 ward on this subject within the last year or two, yet it would not be without 

 interest to pass again over the well-bealen path, and familiarly to reflect upon 

 some of its most important truths, as met with in every day life. It will 

 matter little in what order the subject is taken, so that by the end its most 

 important points have been touched upon. It will be of no advantage to 

 follow any particular pedantic arrangement, or rigid scientific order, as we 

 do not find such in nature. The present lecture he proposed to devote to the 

 consideration of the sources of heat. 



By the sources of heat is merely meant those circumstances which cause 

 the feeling of warmth to the hand, which communicate the same to other 

 bodies, or ignite combustible substances. The common source of artifi- 

 cial heat is what is termed combustion, that is, heat generated by bodies at 

 the moment they are combining by chemical affinity. As one instance of 

 what is meant, a piece of phosphorus may be burned in aporlionof air confined 

 in a glass jar, and will continue to burn so long as the air within contains 

 any oxygen for it to combine with, but when that is consumed it will go out. 

 Just so is it with any other combustible, as a common fire ; cut off' air from it 

 and it is extinguished. In these instances the heat is accompanied with light, 

 which is the case in all ordinary combustions. The heat and light are mo- 

 mentary, but the effects are permanent. Certain substances are produced, in 

 the case of phosphorus a solid, in that of the fire a gas, but in either case no- 

 thing is lost; no such thing as annihilation of either matter nr force ever 

 takes place ; it may be transferred from one place to another, but in most 

 cases it can be followed, and its presence proved. But this 'action can only 

 once produce these phenomena, and therefore it is necessary m fires to keep 

 up a continuous supply. The substance that we now use as fuel, namely 

 coal, is perhaps of all others the best adapted for our wants. Wood is seldom 

 now, at least in this country, thought of as fuel. A piece of charcoal and a 

 bottle of hydrogen gas may be taken as representing the composition of all 

 ordinary combustibles ; whether coal, wood, oil, w:x, or gas, it is for their 

 carbon and hydrogen alone that they are valued. A piece of coal lighted and 

 put in a jar of oxygen gas, will represent the ordinary circumstances of a 

 coal fire, acting with more rapidity, certainly, but in every other circumstance 

 the same. The miniature fire swells with heat, sends out gas, which burns 

 with flame, causing heat enough to expel more gas, and leaving a red hot 

 cinder, which, if there be gas enough, will burn entirely away, leaving a little 

 ash. And now in the jar instead of oxygen is found carbonic acid gas and 

 water, as the whole of the process consists merely in the carbon and hydrogen 

 of the fuel combining with the oxygen to produce carbonic acid and water. 

 The amount of heat produced is perfectly definite. From a given weight of 

 combustible the same quantity of heat is evolved, whether it be burned slowly 

 or quickly, whether under one circumstance or another. The amount of light 

 produced must not be considered as at all indicating the amount of combus- 

 tion or heat, as it Is produced from a somewhat different cause. The flame of 

 hydrogen is very feint, but produces great heat ; the flame of hydrogen, to 

 which has previously been added half of its bulk of oxygen, is scarcely per- 

 ceptible, but its heat, with one exception, is the most intense that can be ob- 

 tained. But bring into this non-luminous flame some solid substance, and it 

 instantly becomes luminous. Not that the substance need consume, for lime, 

 which is unaltered by heat, gives out a light so bright that the eye can 

 scarcely bear it. Light in these cases, then, appears merely to arise from 

 solid substances becoming intensely heated. Coal gas may be burned, and 

 that to any amount, and in the most perfect manner, and yet very little light 

 be evolved, by placing a piece of fine wire gauze on the fop of the glass chim- 

 ney, and lighting the gas after it has passed the gauze. The air is so inti- 

 mately mixed with the gas that the carbon of the gas is consumed before it 

 has been highly heated, and therefore little light is caused. 



All things are combustible ; everything around will burn ; and yet they are 

 all waiting till commanded, so obedient is nature to man's wishes. Why 

 does the candle wait till lighted — why does gunpowder in the cannon wait? 

 It is because they all want some little necessary condition to set them off: 

 like a spring wound up to full tension, waiting but a touch. Sometimes the 

 condition wanted is a little moisture, or electricity, or heat. A wax taper 

 immersed in oxygen does not burn, though its wax is all ready to consume, 

 and has ever been so, whether taken from the mummy or the bee of last year. 



