Rumsey invented the
probang, a medical instrument made of whalebone, to cleanse the throat and stomach Wood wrote "He was much troubled with flegme, and being so one winter at the court at
Ludlowe (where he was one of the counsellours), sitting by the fire, spitting and spewling, he tooke a fine tender sprig, and tied a ragge at the end, and conceived he might putt it downe his throate, and fetch up the flegme, and he did so. Afterwards he made this instrument of whale-bone. I have oftentimes seen him use it. I could never make it goe downe my throate, but for those that can 'tis a most incomparable engine. If troubled with the wind it cures you immediately. It makes you vomit without any paine, and besides, the vomits of apothecaries have aliquid vetietii in them." Rumsey was interested in the medical uses of
coffee and in his
Electuary of Cophy, which appeared in 1657 he gave a prescription for "a new and superior way of preparing coffee" as an Electuray to take when using the provang. "Take equal quantity of Butter and Sallet-oyle, melt them well together, but not boyle them: Then stirre them well that they may incorporate together: Then melt therewith three times as much Honey, and stirre it well together: Then add thereunto powder of Turkish Cophie, to make it a thick Electuary". He also devised a concoction called "wash-brew" which included oatmeal, powder of "cophie", a pint of ale or any wine, ginger, honey, or sugar to please the taste, to which could be added butter and any cordial powder or pleasant spice. The mixture was to be kept in a flannel bag for use when required. This said to be a popular medicine among the Welsh people. Rumsey wrote another work,
Divers new experiments of the virtue of Tobacco and Coffee to which Sir Henry Blount and James Howell wrote commendatory Epistles. In a chapter entitled "Experiments of Cophee" he noted that coffee had the power to cure drunkards. ==Marriage and later life==