Sand is 2–0.05 mm, silt 0.05–0.002 mm, clay under 0.002 mm — the USDA limits, not the engineering ones, which put the silt–clay break at 0.075 mm. The same soil gets different numbers in the two systems, and mixing them is a common and expensive mistake.
Plot your Proctor points. The dashed line is zero air voids — no compaction can ever cross it, so a point above it means an arithmetic error, not a record.
This is the bearing capacity only. Settlement usually governs a real footing on sand long before capacity does, and this does not check it.
An uncorrected blow count is not a soil property — it is a property of the hammer, the rod length and the depth. Two rigs will give different N in the same ground.
Take a walnut of soil, wet it until it glistens and knead until it is uniform. Then work down these questions. A trained hand gets within one class of the laboratory, which is why the method has outlived every gadget meant to replace it.
O — leaf litter and peat, organic, sits on top.
A — dark topsoil, mineral with organic matter mixed in, where roots and life are.
E — pale, leached; the clay and iron have been washed downward out of it.
B — subsoil, where that clay and iron accumulated. Often redder or blockier.
C — weathered parent material, still recognisably the rock it came from.
R — the bedrock itself.
Not every profile has every horizon. An E horizon means water moves down through this soil, and a strongly developed B means it has been doing so for a very long time.
Dilatancy — pat a wet ball in your palm. Water appearing on the surface, then vanishing
when you squeeze, means silt. Clay does nothing.
Dry strength — let a pat dry, then try to break it. Powders easily is silt; needs real
effort is clay.
Toughness — roll a thread at the plastic limit. A tough thread means clay; a thread that
crumbles at 3 mm means silt or very lean clay.
Effervescence — a drop of dilute HCl. Fizzing means carbonate, and that changes the pH,
the structure and what will grow.