The various types of coal stoves are listed and described briefly below. All turn of the century coal stoves are cylindrical. Even the small franklin heaters like my Stanley Argand are cylindrical. All wood stoves from this time period are boxes. So it is easy to tell a wood stove from a coal stove. Now certain coal stoves were designed to be able to burn wood also, but; as a secondary fuel, these are also cylindrical. It can be confusing to some one just becoming acquainted with stoves and the terminology that goes with them.
Oak Stoves. Oak stoves are extremely common and most all manufacturers made them. An Oak stove is by definition a direct draft stove. That is the combustion air comes in at the bottom under the grate and the exhaust goes straight out of the top. These were designed to be able to burn anything. They vary greatly in quality and levels of craftsmanship. Most of the economy stoves are oak stoves, however; the top of the line oaks are quite superior. You just have to know what you are looking at.
There are two basic variations of the oak stove design. One is the type that has an indirect back pipe option applied to it for the burning of coal. These on the outside look just like base heaters, but; they are still oaks. These back pipes have a divider down the inside center of them to direct the exhaust gasses in a downward, then upward "U", direction of flow to increase the radiant surface area of the stove. These back pipes make the stove quite effective and efficient at coal burning, but; differ from a base heater as a base heater has a much longer and more involved heat exchange system in it.
The second variation of an Oak stove are those that fall under the, "hot blast," category. These are extremely well designed stoves that are designed for Bituminous coal as their primary fuel. Bituminous coal has radically different combustion characteristics than Anthracite. These stoves supply super heated secondary air just above the fire bed to burn the large amount of hydrocarbon gas that is released from Bituminous Coal. In fact most of the heat value in Bituminous is found in the hydrocarbon and if these are not efficiently burned the heat value is totally lost and all you get is a bunch of smoke and soot build up.
There are basically three types of base heaters or (base burners) These two terms are interchangeable and lead to confusion. There are however, large differences in the various designs of base heaters. What they all have in common is that they are all made to burn Anthracite Coal as their principal fuel. In fact the only base heaters that can get away with burning wood in them are the types like the Glenwood 6's and 8's. There are many other foundries that made this design of stove as well. They are all fairly similar in design and construction. These are an advancement of the Oak stove design with the edition of the base heating element. These are recognized by having the base heating tubes on the EXTERIOR rear of the stove and the exhaust port about 1/3 of the way between the top of the fire pot and the top of the stove. The exhaust goes out of the rear opening outside of the stove, then down under the ash pit, then back out side into a parallel tube to then exit.
The next type is the MICA BASE BURNER. These are strictly Anthracite heaters. Burning wood in these destroys them. These were termed. "Radiant," stoves because the front and sides are made of mica windows to allow a far greater amount of the direct radiant heat of the fire to escape into the surrounding area. The base heating exhaust path can be quite complex on some of these stoves. Some of them had triple pipe heat exchangers on them. Many of these stoves also have what is called a, "double heating," feature on them. What this means is that the stove has an internal plenum that makes hot air like a furnace as well as provides radiant heat.
The third design is those base heaters that have an internally suspended fire pot. These stoves are also for Anthracite Only. This type of stove is unique in its design. It is the only stove ever made that has a fire pot that is insulated from heat loss by the fire's own hot exhaust gasses. The hot exhaust in these stoves GOES AROUND the fire pot and the actual fire itself before they descend down into the bottom of the stove, circulate, then exit up a back pipe in the rear of the stove to exit. These stoves are common in smaller sizes. They made big ones two but they don't seem to be as common for some reason. I have one of the largest types of this design. An Our Glenwood No 13. This stove holds a 100 pounds of coal. These are fairly rare however.
I hope this clears up some of the confusion. If you want more information just ask.