The Patent Office had its second fire on September 24, 1877. This fire happened in the new “fire-proof” building whose construction had begun in 1836. The building was fireproof but the contents were anything but.

On that chilly morning in September, employees in the west wing of the building had a fire started for warmth. Sparks from the fire landed on the roof and ignited a gutter screen. Quickly, half the building seemed to be engulfed in flames. Employees of the Patent Office and fire companies from as far away as Baltimore worked tirelessly to save as much of the building and information contained inside as possible.  Still the fire left the north and west wings of the buildings gutted shells.

The monetary lose was much worse than that of the fire in 1836. For months after the fire, great efforts were made at a very high cost to replace the artifacts. Of the 114,000 models that were housed in the building, 87,000 were destroyed. 600,000 prints of original drawings were lost and had to be reprinted. Original drawings and models of 31 patents were destroyed. These were restored using only the specifications. Ultimately though, no patents were completely lost in the fire.