What's the serial number on your 1899?
Every time I encounter one in .38 Special I try to push the serial number back to see approximately at what point it was released in .38 Special. There's some confusion about that.
As for your particular gun, there's hardly any bluing left, but the hard rubber grips appear to be in fantastic shape and the metal is in very good shape.
If the barrel and chambers are in good condition, I'd not be surprised to see value at between $750 to $1000 to a collector.
I'll have to hit the books to figure out what the break top is. What's its serial number, as well? That will pin down the specific series. That one, though, is chambered in .38 Smith & Wesson, an earlier round that used a 146-gr. bullet at approximately 600 or so FPS. It was a very popular cartridge in its time.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.