On the Replenishment of Celestial Vessels and the Perpetuation of Motion Above the Firmament

In my workshop this morning, whilst grinding pigments for the drapery of the Virgin — that ultramarine which must be layered thin as the membrane between artery and vein — a most extraordinary rumor reached me through a channel I dare not name. It speaks of the year 2026, and of men who propose to feed fuel to machines that already circle the heavens, as one might water a horse at a trough along the road to Bologna. I must set down my observations, lest I forget: First — that men have indeed placed vessels above the sphere of air. This alone staggers the mind. I have studied the flight of kites, of birds, of my own devices with helical screws, and I know how jealously the air guards its upper reaches. Yet these future artificers speak not of air but of the void itself, that emptiness beyond the moon which Aristotle denied and which I have long suspected. Second — they speak of electric propulsion. Electricity — I have seen the amber stone attract chaff, and the torpedo fish stun the hand of the fisherman. Can such a force, so subtle, so capricious, truly move a vessel through the heavens? I note this for further inquiry. If a force can move blood through the smallest capillaries of the liver, perhaps a kindred subtlety can push iron through nothingness. Third — and here is the matter that most delights me — they propose to refuel these machines whilst they remain aloft. This is hydraulics translated to the celestial sphere! I who have designed aqueducts, locks for canals, pumps that lift water against its nature — I understand the principle. A vessel is useless when its reservoir is spent. But to join two moving bodies in the void, to transfer fluid from one to another without spilling — Dio mio, this requires a coupling of extraordinary precision, like the joint between the femur and the pelvis, ball within socket, sealed by its own geometry. Questions I must investigate: — What fluid do they use, if not water nor oil? — How does one prevent the fluid from boiling away where there is no air to press upon it? — Is the coupling mechanical, or does some magnetic sympathy draw the parts together? They say this is merely a study, not yet a contract. I understand this well. How many of my own machines remain as drawings only? Yet the drawing is the father of the deed. I say: let them study. The canal at Milan began as a sketch in a notebook not unlike this one. Technique and vision are one discipline. The hand that paints the angel's wing must also design it to fly.