This is the study of mechanical objects, industrial processes, and useful tools. Those skilled in the study of technology will be some of the main drivers of the world, as they craft varied and wondrous invetions that may change society completely, whether they be a powerful weapon or a new mode of transportation.
At game start the level of technology available will be that of the use of cast iron. This means that weapons will be at the general level of swords, spears, crossbows and hammers, whereas industrial tools are normally basic pickaxes and shovels for mining, and ploughs and scythes for farming. All this can rapidly change, however, with the development of novel smelting techniques, unearthing of new ores, and ingenious plans.
These are some of the things you might making in the future. Of course, it is perfectly possible to devise your own ideas of things to invent and develop. It is important to note that discoveries must follow a path of progression; it would be impossible to invent muskets before gunpowder, for example.
Weaponry:
Mundane: