Traveller's typewriters or portable typewriters were smaller, lighter typewriters that began to be produced towards the end of the 19th century. Blickensderfer's portable typewriters were some of the first to be made. Blickensderfer also developed the first electric typewriter, with a type wheel. It is believed that Mina may be using a Columbia portable typewriter, which came onto the market in 1885 and weighed only 6 pounds, and may also have been used by Bram Stoker to type up Dracula.
Click here to read an article from 1913 on portable typewriters