[93]. Annular conoidal greenhouse boiler.

[94]. Vertical cylindrical, closed top greenhouse boiler.

The last four are types of the greenhouse boilers most in use. They are usually of wrought iron, and all seams welded.

[95]. Back boiler for ordinary register grate.

[96]. “Boot” boiler.

[97]. Scullery, or wash-house boiler.

[98]. Scullery, or wash-house boiler, heated by steam. In public laundries these are usually rectangular in plan.

[99]. Coil boiler, used for small greenhouses, &c.

[100]. Sectional, or “Tubulous” boiler. Root’s, and others, are on this principle. They are constructed of simple pipes and T or L pieces, usually bolted together.