A Tour in Scotland and Voyage to the Hebrides, 1772 (1774 & 1776) by Thomas Pennant (volume 1 online here; volume 2 online here).

Vol 1, p68

"May. 28. Saw at Mr Bernard Burton's, a pleasing sight of twelve little industrious girls spinning at once at a horizontal wheel, which set twelve bobbins in motion; yet so contrived that should any accident happen to one, the motion of that might be stopped without any impediment to the others."