History of temperature scales: Early thermometry used dilute wine (alcohol) as the thermometric liquid. The first widely adopted empirical temperature scale developed on that basis was the ______ scale.

Introduction / Context:
The evolution of temperature scales reflects advances in thermometry. Before mercury thermometers became standard, alcohol (often called dilute wine) was used because of its low freezing point and visible expansion. Recognizing which historical scale was tied to alcohol thermometry clarifies the lineage of today’s Celsius and Kelvin scales.

Given Data / Assumptions:

• Alcohol thermometers preceded accurate mercury instruments.
• Réaumur proposed 0° at the freezing point of water and 80° at the boiling point (at standard pressure).
• Fahrenheit’s work involved mercury and different fixed points; Celsius later defined the centigrade scale (reversed in modern usage).

Concept / Approach:

The Réaumur scale was historically implemented with ethanol (dilute alcohol), whose thermal expansion was suitable for capillary thermometers of the time. The scale’s span from 0° to 80° between the water ice and steam points was practical for laboratory use. This fits the prompt’s explicit cue about dilute wine as the thermometric liquid.

Step-by-Step Solution:

Verification / Alternative check:

Historical references cite René-Antoine Ferchault de Réaumur (1730) using alcohol thermometers; Daniel Gabriel Fahrenheit (1724) standardized mercury thermometers with his own scale; Celsius (1740s) defined centigrade, later inverted and renamed.

Why Other Options Are Wrong:

Kelvin: Defined later from absolute zero and triple point; not empirical alcohol-based. Celsius/Fahrenheit: Though empirical, they are not the ones specifically linked to dilute wine in the original implementations referenced here.

Common Pitfalls:

Assuming “first” always means Fahrenheit chronologically; the question’s alcohol clue points to Réaumur’s well-known alcohol scale (0–80).

Final Answer:

Réaumur