384 JOURNAL OF SCIENCE. 
acutely at both.’ They are slightly curved like those of S. 
fluviatilis, and appear quite smooth when viewed with a \-in. 
objective ; the only difference I can detect is that they are 
slightly more slender than the one drawn by Bowerbank. I have | 
not been able to consult any work giving full descriptions of the 
British and European fresh-water sponges, and as I have only 
observed the skeleton spicules, it would be absurd to try to 
identify my specimens with any sponge already described. Mr. 
Haswell has lately described some Australian fresh-water 
sponges (Proc. Linnean Soc. N. S. W., Vol. vii. p. 208), but they 
all seem to differ from my specimens. CHAS. CHILTON. 
BLOW-PIPE TESTS.—While experimenting several months 
‘ago with Major Ross’s Hydriodic acid tests for antimony, lead, 
cadmium, and bismuth, and finding them generally unsatisfactory, 
I accidentally hit on a very characteristic reaction for antimony 
and lead, giving in fact the results which Major Ross asserted 
would follow from his tests. Antimony :—The supposed anti- 
mony salt is mixed with sulphur and iodide of potassium (equal 
parts of test and each of the re-agents). The mixture is heated 
before the blow-pipe on charcoal, and a volatile white incrusta- 
tion will appear. If now the hot slag be touched with a drop of 
H.Cl., the charcoal being held so that the resultant fumes flash 
over the incrustation, the white incrustation at once changes toa 
light red. The hydriodic acid test should give the same result, 
but does not—or does so feebly. Lead: The supposed lead — 
salt being treated as above, the characteristic dark yellow in- 
crustation of lead changes at once.to a light canary yellow. 
ALEX. STUART. 
sCIENCE-TEACHING IN: SCHOOLS. 
————_+_- + 
BY PROFESSOR T. JEFFERY PARKER. 
1s led Peg hese 
Mr. G. M. Thomson’s able article in the January number of © 
this Journal brings before us with renewed force the urgent 
necessity of some sort of graduated system of instruction in — 
Natural Knowledge, adapted for use in primary and secondary 
schools. In languages and in mathematics such a system is in 
universal use, and the pupil is carried by easy gradations from 
simple addition to the binomial theorem, from the ever-edifying 
Balbus to Virgil and Horace. But in the natural sciences how © 
few seem to recognise the necessity for anything of the kind! 
To learn “science” often means to attend detached classes on © 
divers subjects, one term perhaps being devoted to some branch 
of physics, another to physiology, another to botany, and so on, 
each class being wholly independent of all the rest, and all of 
them being taught without attempting to make the pupil verify, 
