As Sapphire said, it is a "kerosene hanging lamp" that has been electrified.
Yours was made to "pull down" from the ceiling to light, fill with oil, etc, and then raised back up to the desired height.
There were dozens of manufacturers of kersosene lighting fixtures and the best source for finding out "who made it" or to "date it" is to research the old wholesale/retail "trade-supply catalogs", ..... Sears Roebuck, etc.
Of course, locating copies of those old "supply house" catalogs is a chore in itself.
The wife has a "wholesale" catalog that is titled .... Baltimore Bargain House that is 9 1/2" X 13" X 5/8" in size and contains 320 pages and is the "Spring 1908" edition ... which retailers would order their goods from..