Bone boiling appears to be some sort of rendering operation, possibly for making soap.  I found an article from the New York Times ca 1895 complaining about a bone boiling operation in Westchester that had the effect of running most of the rest of the neighborhood out of their homes.  Interestingly enough the local health department couldn't find anything wrong with the bone boiling operation so that it could be closed down.  I have been reading building restrictions forever, but the article in the Times is a real eyeopener -  talk about laissez-faire.    Also note that the rest of the restrictions include a prohibition on putting up a building with a flat roof - must be code for "shanty".