Given the following reasoning and answer, what was the question? The relevant information is: In 1886, Carl Gassner obtained a German patent on a variant of the Leclanche cell, which came to be known as the dry cell because it did not have a free liquid electrolyte.
The answer: 1886
The question Passage: In 1886, Carl Gassner obtained a German patent on a variant of the Leclanche cell, which came to be known as the dry cell because it did not have a free liquid electrolyte. Instead, the ammonium chloride was mixed with plaster of Paris to create a paste, with a small amount of zinc chloride added in to extend the shelf life. The manganese dioxide cathode was dipped in this paste, and both were sealed in a zinc shell, which also acted as the anode. In November 1887, he obtained U.S. Patent 373,064 for the same device.

Question: Based on this passage, when was the first dry cell battery invented?