Forms of precipitation:
Sleet: Pellets of ice formed by the freezing of raindrops or the refreezing of melted snowflakes as they fall through a subfreezing layer of air near the Earth's surface. Sleet pellets bounce when striking the ground.
Glaze (Freezing Rain): Supercooled raindrops that freeze instantly upon contact with cold surfaces on the ground, forming a smooth ice coating.
Hail: Hard, rounded balls or lumps of ice ($\gt 5\text{ mm}$) formed inside convective cumulonimbus storm clouds by alternating upward and downward drafts.
Snow: Ice crystals in the form of hexagonal flakes directly sublimated from water vapor.

Recording rain gauge mechanisms:
Weighing-bucket type raingauge: In this instrument, precipitation falling into a collector bucket is placed directly on a spring-balance or load-cell platform. The weight of the accumulated catch is continuously measured and recorded on a rotating drum clock or data logger. Because all precipitation (rain, snow, hail) remains in the bucket, it records the direct cumulative mass/depth of precipitation over time without needing siphoning.
Tipping bucket gauge: Records rainfall increments (tips) to measure rainfall rate/intensity.
Float type gauge: Siphons periodically when the chamber fills.
Symons' gauge: Non-recording type.

Empirical rainfall-runoff relationships developed for Indian catchments:
(A) Binnie's percentages: Developed by Sir Alexander Binnie for rivers in Madhya Pradesh (III) (formerly Central Provinces, based on observations near Nagpur).
(B) Strange's curves and tables: Formulated by W.L. Strange for the Bombay-Deccan catchment (I), classifying catchments as good, average, and bad.
(C) Barlow's tables: Developed by T.G. Barlow based on observations of 19 small catchments in Uttar Pradesh (II).
(D) Lacey's formula: Developed by Gerald Lacey for alluvial plains of the Indo-Gangetic plain (IV), incorporating catchment factor \(S\) and monsoon rainfall.