On December 15, 1836 the building temporarily housing the Patent Office caught fire. All of the approximately 10,000 patent documents from 1790-1836 and some patent models were destroyed. https://10millionpatents.uspto.gov/index.html According to the U.S. Patent Office, only 2,845 patents were restored. These patents were given a new number beginning with the letter 'X'. A list of the X Patents is available in Name and Date Patents: July 31, 1790 - July 2, 1836 from Patent and Trademark Depository Library Program.
Many patent documents with historical significance were lost in the fire. If you are researching U.S. inventions from 1790-1836 it may be difficult or impossible to find the original patent. However, there are other ways to research inventions from this time period. Below are some databases, books, and magazines that can be helpful in finding information about an invention from this time period.