Glass Pen Holder James Adair Adairack #3 Pittsburg Pa.

Bidding on a vintage clear glass pen holder. Both sides come up to form a valley w the pen lays. Written in the glass -PATENTED OCT. 24, 1899 JAN 30 1900. ADAIRACK NO3 JAMES ADAIR PITTSBURG PA. The bottom is sllightly worn due to age. I know nothing about this except the person that I bought it from said it was an antique pen holder and my husband has used it for several years holding his mont blanc pen on his desk. It measures approx. 4" long and 1 1/2" tall. Thanks for looking.