I have just bought a bowie knife that I believe is a james black. The only issue is that the marking has been scratched off. I have heard that there is an acid that may reveal that marking. If anyone could help me with some info about this i would be very thankful. Thanks in advance for any help
I'm not certain what part of the country you're in but you have a couple avenues of approach. And there are other methods to include paying a professional appraiser.
One is your local or state Historical Museum, some are willing to do that kind of work for a minor fee as it brings them in some coin. Be prepared to wait a while for the work.
Option two is actually your local PD, many times their crime lab will do such work, again for a fee, which they do as training. I've had a knife fully analyzed that way and it cost me $120-150 IIRC. I simply went in and asked to speak to a Detective, explained what & why I wanted a particular analysis done and I was passed onto their Criminal Investigation Forensics crew. They have an enormous back log so once again expect a good long wait. At the time I was told they would let me know when they had a new hire and it would be used as a kind of prelim or OJT test. The supervisor was quite cool about it. Took about a year, but I have a cast iron guarantee that the "Arkansas Tooth Pick" I bought for $40 dates to the 1860's +/- 20 years. And the maker mark & date stamp on the tang are legitimate. I now have a $1000 knife instead of a $40 knife so IMO it was well worth the wait.