… and diatomite) and similar siliceous earths, whether or not calcined, of an apparent specific gravity of 1 or less. …
Explanatory notes
… and diatomite) and similar siliceous earths, whether or not calcined, of an apparent specific gravity of 1 or less. … very light. Their “apparent specific gravity”, which must not exceed 1, is to be taken as their effective weight in … “tripoli”, they must not be confused with the true tripoli known as “rotten‑stone”, which, since it results from the …