"Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible."
|6183531||Mineral wool plant substrate|
Mineral wool plant substrate formed of a coherent matrix of mineral wool having 99.9 to 75 wt % mineral wool and 0.1 to 25 wt % of an organic substance. Clay may be included in the matrix. The matrix may be in the form of a pellet....