Henry Gardner is mentioned frequently in Hopper’s diary. After being released from Sing Sing, Gardner, according to Hopper, succeeded working as a “Cooper.” Like many other outmoded professions mentioned by Hopper, human coopers are largely gone and forgotten.

Coopers used timber to craft casks such as barrels, drums, and hogsheads for storage and transportation. 19th century coopers were divided into three main specializations: wet, dry, and white. Wet coopers made casks that could hold liquids such as wine and whiskey. Dry coopers had it a bit easier. Their barrels did not have to be water-tight, and were made to store such items as flour and corn meal. White coopers made household and kitchenware, such as buckets and butter churns.¹

Many 19th century coopers worked on slave plantations---in fact, many were slaves---because of the amount of hogsheads needed to ship tobacco. Coopers also tended to work on military and merchant vessels, as storage casks were a necessity aboard ships. Back then, coopers were needed practically everywhere, as there was always food that had to be stored away from vermin, or material items that had to be transported, or butter that had to be churned. Coopers were very important people.²

For instance, the cooper at New Salem when Abraham Lincoln lived there was Henry Onstot. He was prosperous in the extreme, as his barrels were highly demanded by the nearby grist mill. Interestingly, his cooper’s shop is the only original building in the historical recreation of Lincoln’s New Salem (lincolnsnewsalem.org). 

According to Merriam Webster, the products of a cooper’s work are known as “cooperage,” which is for some reason hilarious.³

Sources:

1. https://lincolnsnewsalem.org/barrel-making-in-new-salem-what-is-a-coope…

2. https://www.history.org/ALMANACK/LIFE/TRADES/tradecoo.cfm

3. https://www.merriam-webster.com/dictionary/cooperage