Zeynep Özlü's archive-based research names Mehmed Reşid Ağa as a palace snow and ice official in a 26 June 1805 record. It also describes snow stores around Istanbul and Üsküdar in the early nineteenth century; this does not establish one empire-wide system.
Separate details in the record. Extract source location, route, delivery point, product name, quantity and price as separate fields where documented. Retain the record's own units and wording.
Locate the storage link
Separate records about a store, ice house or point of sale from transport documents. Do not treat records for the same product but different dates or institutions as equivalent.
Use evidence for loss calculations
If both departure and arrival quantities are documented, calculate their difference and define it. If either quantity is absent, do not estimate melt rates or price premiums.
Method carried into today's work. In modern cold transport too, keep source, route, storage, delivery time and measurement records distinct. A historical analogy does not replace shipment measurements.