This one is embossed around the flat side to the top rim: Patent/ Spratts// 1850. These may have been produced after James Spratt sold his Lightning Protection business in 1851 or 1852. This style of LRI has some neat characteristics to the glass. For one thing the embossing '1850' on the face of the tab is read from the base upward, as opposed to reading from top to base like on all other Spratt LRIs that I've seen. On all of this style I've seen there is a lump of excess glass over the '0' in 1850. The colors tend to be mostly dark green, with fewer being more of an aqua shade. Size: about 1 3/4" tall and 1 7/16" across the base. Unknown previous ownership.