Another early case bottle, this one without a pontil scar. It does have a diamond or square pattern on the bottom that is off-set from the center of the bottom The mollette (tool used to push up the bottom) mark is about centered.
I have a black glass bottle that is sort of an odd-ball in my collection. I don't know if the bottle is British or American or from someplace I haven't considered. Can readers here tell me if this form is familiar in local digs?
The bottle was blown in a turn-mold, and has a lip that suggests to me a British beer/ale bottle. The volume is 24 fluid ounces, which is a beer bottle size in the USA. The sloping shoulders with the skirted bead-lip make it stand out on a shelf of early wine bottles. I'm only guessing at a date of 1840-60 for this bottle if it's a British bottle, and 1860-70s if it's an American bottle.
By protecting do you mean preventing them from fading? Keep them in a room that doesn't get sunlight, for example using blackout curtains. Or if there is sunlight don't let it be direct. Low humidity...