Here is an antique silver plated jigger marked “Meriden B. Co. 01”. This style jigger was included in the 1886-87 Meriden Britannia Catalog, page 21. Several of my photos were taken on that page of the catalog. It was offered in two base metal options, the No. 2 was a white metal base and the No. 01 was a nickel silver base, which this jigger is. It stands almost 4 inches tall and is a nice heavy weight.
The script monogram is difficult to read. It looks like ” R G H” to me but you might see something different.