The use of leather was an important part of the 19th century. Primarily they tanned their leather with a "vegetable" tanning process, that means they used bark, vegetable scrapes, etc. to make their tannic to tan the leather. I found this web page that is for re-enactors about the care and the use of leather during the civil war. It has a lot of good information in there and if you're wondering how your character took care of their leather saddles, boots, etc. you might find this a very helpful website.
Article on leather in 19th Century by David Jernigan & Ken R. Knopp