That looks like the H&A "Automatic" (automatic ejecting, as opposed to hand ejecting) revolver. They were made in .38 S&W caliber from 1885 to 1907 and in .32 S&W from 1890 to 1907. The folding hammer spur was an option on both the H&A revolvers and on the Merwin & Hulbert revolvers that were made by H&A.
H&A revolvers were decent quality, never up to S&W, but quite a bit better than some of the other small revolvers of the period.
Jim