It is desirable to arrange the heating surface in such a way that the feed water entering the boiler at its lowest point is heated gradually as it ascends, until toward the superior part of the flues it is raised gradually into steam; but in all cases there will be currents in the boiler for which it is proper to provide.

A pump M, called the hot water pump, lifts hot water out of the hot well to feed the boiler, and another pump N lifts cold water from a well or other source of supply, to maintain the supply of water to the cold water cistern, in which the condenser and air pump are placed.

A.The general mode of blowing off the boiler is to allow the water to rise gradually for an hour or two above the lowest Working level, and then to open the cock communicating with the sea, and keep it open until the surface of the water within the boiler has fallen several inches; but in some cases a cock of smaller size is allowed to run water continuously, and in other cases brine pumps are used as already mentioned.

Now when the fire had grown red and hot, the bo'sun half filled the boiler with sea water, in which he placed the meat; and the pan, having a stout lid, he did not scruple to place it in the very heart of the fire, so that soon we had the contents boiling merrily.

Q.Will this rule give the proper dimensions of the pump for feeding the boiler with water? A.No; it is necessary in practice that the feed pump should be able to supply the boiler with a much larger quantity of water than what is indicated by these proportions, from the risk of leaks, priming, or other disarrangements, and the feed pump is usually made capable of raising 3-1/2 times the water evaporated by the boiler.

Q.Then the chief difference in the proportions established by Boulton and Watt, and those followed by the other manufacturers you have mentioned is, that Boulton and Watt set a more powerful boiler to do the same work?

"STEAM-BOAT EXPLOSION.Captain Duncan, of the 'Swan,' reports that the tow-boat, 'Daniel Webster,' burst her larboard boiler on the 6th instant, while towing in a vessel over the South-west Bar.

I was even able to do justice to the abominable food set before us at dinnergreasy sausages and a leathery beefsteak, served on dirty plates and a ragged table-cloth that looked as if it had been used to clean the boiler.

You say, can't you wash out a boiler without a force pump?

If your flues have been leaking badly, and you have expanded them, it would be well to test your boiler with cold water pressure to make sure that you have a good job.

Q.Supposing, then, that you had to proportion a boiler, which should be capable of supplying steam sufficient to propel a steam vessel or railway train at a given speed, or to perform any other given work, how would you proceed? A.I would first ascertain the resistance which had to be overcome, and the velocity with which it was necessary to overcome it.

The Gallant Sex (A woman engineer has been dismissed by the Board of Education, under their new rule that women shall not attend high pressure boilers, although her work has been satisfactory and she holds a license to attend such boilers from the Police Department.)

In the annex beyond the kitchen, a separate building contains the boilers and engine room and the electric-light plants.

A cock for emptying the boiler is usually fixed at the bottom of the fire box, and it should be so placed as to be accessible when the engine is at work, in order that the engine driver may blow off some water if necessary; but it must not be in such a position as to send the water blown off among the machinery, as it might carry sand or grit into the bearings, to their manifest injury.

The water for replenishing the boiler is pumped into the small cistern on the top of the pipe; and it follows from these arrangements that when the buoy falls, the rod opens the small valve and allows the feed water to enter the pipe, which communicates with the water in the boiler; whereas, when the buoy rises, the feed cannot enter the pipe, and it has, therefore, to run to waste through an overflow pipe provided for the purpose.

The performance of this course by the smoke is what is termed a wheel draught, as the smoke wheels once round the boiler, and then ascends the chimney. 86.

We have recently seen the Freeborn, the Pawnee, and the Harriet Lane, when assailing the rebel batteries on the James and the Potomac, compelled to take positions at the distance of two miles, and to keep constantly moving, and compelled consequently to throw away most of their costly ammunition in uncertain shots, at the same time that they were constantly exposed to shots which might destroy their engines and explode their boilers.

A.In the setting of marine boilers care must be taken that no copper bolts or nails project above the wooden platform upon which they rest, and also that no projecting copper bolts in the sides of the ship touch the boiler, as the galvanic action in such a case would probably soon wear the points of contact into holes.

To prepare dye boiler, put in 2 lb. logwood, boil twenty minutes.

She had a little passage screened off, and in this were fitted up boilers for coffee and soup, tables for cutting up meat and vegetables, and even a machine for cutting up the bread.

It is better, however, to make the sectional area larger than this, and to work the boiler with the damper sufficiently closed to prevent the smoke and flame from rushing exclusively through a few of the tubes.

"They had to get out of her when Pedro cut her engines out and lowered her boilers.

These plates are of the same manufacture as those for making boilers, varying in thickness from three-eighths to three-fourths of an inch.

If you were running in a hilly country how would you manage the boiler as regards water?

I know that the hardware people who manufactured our clothes-boiler, down in the laundry, did not design it as a toy bass-drum for the children to bang on on the morning of the Fourth of July.