The firebox is the main area for generation of steam, but the products of combustion must then be conveyed to the smokebox, through tubes. These tubes must be designed to extract the maximum amount of the remaining heat and transfer it to the surrounding water. Too small tubes impose too much restriction on the flow of gasses, too large and not enough of the hot gasses will be in contact with the walls. Similarly if they are too long. Two types may be used :- Small Tubes are approximately 2 inches diameter and a boiler may contain several hundred tubes. A regular job was sweeping the tubes, or blowing them through with a steam lance. Flue Tubes were often used on large engines and these were between 5 to 6 inches diameter. Smaller tubes, known as superheaters, were placed inside the flue tubes and these carried steam from the regulator to the cylinders thus super heating the steam to provide more power. Only a relatively small number of these tubes were used in each boiler. Narrow gauge engines will use smaller tubes.

Water Pipe for smoking Cannabis (Bong)

Tubes that run the length of the boiler, through which the hot gases from the firebox pass to heat the water that surrounds the tubes.

Narrow parallel-sided passages beneath the caps of polypores and boletes, where spores are produced.

spore-bearing structures in polypores and boletes, aligned vertically and terminating in openings on the pore surface.

with regard to fungal fruitbodies, tubular structures lined on the inner surface with basidia

What everyone automatically calls the Boomwhackers Musical Tubes (because that's what they are!). Tubular: Of the nature of the Tubes (in other words, very cool!).

The "tubes" are medically known as the Fallopian tubes. There are two Fallopian tubes, one on each side, which transport the egg from the ovary to the uterus (the womb). The Fallopian tubes have small hair-like projections called cilia on the cells of the lining. See the entire definition of Tubes

see Fallopian tubes.

Small devices placed in the eardrums to prevent fluid build-up in the ears.

amount of antibody needed for each test tube used in a particular assay

(see Extension tubes)