In Heidegger's day, some entities were always ready-to-hand (subsisting as veiled). He offers natural materials as an example. Natural materials are accessible but, in themselves, they do not require production. "Hammer, tongs, and needle, refer in themselves to steel, iron, metal, mineral, wood, in that they consist of these. In equipment that is used, 'Nature' is discovered along with it by that use--the 'Nature' we find in natural products" (BT, p. 100). The produced gear itself indicates elemental structures that are always in the background, always veiled, always ready-to-hand.
Heidegger next describes how Nature (Gaia) becomes unveiled when it is considered as present-at-hand. Present-at-hand is his term for considering entities as mere entities with properties without consideration of their being. When the being of Nature as ready-to-hand is disregarded, "the Nature which 'stirs and strives', which assails us and enthralls us as landscape, remains hidden" (BT, p. 100). The merely instrumental present-at-hand perspective that sees natural matter as natural resources is the disenchanted world view. "For love expires as soon as gods have flown" (Holderlin).
A clock taken merely instrumentally as present-at-hand forgets the background understanding of the light of the sun glancing off the earth's atmosphere as our planet revolves in its involvement. It forgets our rolling around the sun in the role our planet plays in the cosmos. The tick-tock merely signifies in the present-at-hand when we forget the essence of time and believe that "time is money". Taking time authentically, "we tacitly make use of the 'sun's position', in accordance with which the measurement of time gets regulated in the official astronomical manner" (BT, p. 101).