unsensible

"Hear, hear," and Joanna passed out of the conversation, for who was going to waste time either taking up or taking down a silly, tedious, foreign, unsensible notion like ploughing grass?...

There is no breeze, no slightest shift of air-particles; yet down the gorge comes this cloud,--a cloud unsensible except to nostrils,--eddying as if swirling around the edges of leaves, riding on the air as gently as the low, distant crooning of great, sleepy jungle doves.