The brass bar with the sliding weight is marked in whole grains from zero to 120. It is also marked in .1 grams from zero to eight. One pan is removable and it comes with a set of weights, two 50 grams, one twenty grams, two 10 grams and one 5 grams.
Overall length is ~10-1/2" and it is ~7-3/4" tall. It has a metal tag on the back which says "Henry Troemner" maker, Philadelphia, Pa., Capacity 4 OZ, No. 6. No other marks, I estimate it to be late 19th century. A very nice little scale.