What does Rogers Silver marked "IS" mean?

The International Silver Company was organized under the laws of the State of New Jersey on 19 November 1898. Immediately upon organization, the company bought the total capital stock of the following companies: Barbour Silver Company (Hartford), *Holmes & Edwards Silver Company (Bridgeport), *Manhattan Silver Plate, (Lyons, New York), *Meriden Britannia Company (Meriden), *Norwich Cutlery (Norwich), *William Rogers Manufacturing Company (Hartford), Rogers Cutlery (Hartford), Rogers and Brothers (Waterbury), Rogers and Hamilton (Waterbury), Wilcox Silver Plate (Meriden), Watrous Manufacturing Company (Wallingford), Standard Silver Company, Ltd. (Toronto, Canada). <a rel="nofollow" href="http://www.lib.uconn.edu/online/research/speclib/ASC/findaids/ISC/MSS19800008.html">http://www.lib.uconn.edu/online/research/speclib/ASC/findaids/ISC/MSS19800008.html</a> Some more information can be found here: <a rel="nofollow" href="http://www.tias.com/9080/InventoryPage/1580016/1.html">http://www. ...  more