SIR ROBERT ROBERTSON has recorded in NATURE the results of some determinations of the density of water from the Dead Sea1. We had also determined independently the density of two samples from different places by (a) the use of a 25 c.c. pyknometer, and (b) a differential method employing two sinkers of nearly the same dimensions. The uncertainty in either method is about one in 105. In none of the six determinations made could we detect any significant difference between water from the Dead Sea and redistilled water from the laboratory.
NATURE, 133, 611, April 21, 1934.