SCIENCE IN SECONDARY SCHOOLS. 151 
Burn some of the calcium obtained in oxygen and prove that the white 
substance obtained is identical with quicklime. Therefore quicklime is a 
compound of calcium and oxygen. , 
Gas . : F { Carbon 
Chalk , ilk Oxygen 
Quicklime . ' ; p estate, 
Oxygen 
Many objects are suitable for such courses—e.g., the candle, commor. salt, 
hematite, &c. 
B. Some teachers prefer to take the work as a problem rather than as 
subjects. Much of the conventional ‘subject’ matter naturally arises when this 
treatment is adopted, and each suitable occasion for experimental inquiries 
germane to the general inquiry is taken. Moreover, the manipulation and 
laboratory practice arise as a necessity in the course of the investigation and 
the various subjects are correlated. Of course, both these ends should be 
attained whatever the method employed. But in ‘subjects’ there is a strong 
temptation to take elementary practice as an end in itself; something to be ‘ got 
through.’ There are few things more unattractive and dehumanised than such 
courses, which seem absolutely pointless to the boy. For example, he does not 
feel the need of accurate weighing, determination of density, specific gravity, 
&c., and he has no mental picture of any problem on which such matters bear. 
When they are not done as ‘ends in themselves,’ but taken as they occur as 
necessary machinery in the course of an investigation, their apparent pointlessness 
disappears, and the boy is at least reconciled to them as necessary evils. 
In ‘subject’ courses also so much time is often taken over the laws and 
their establishment that the applications and mavhines are never reached; of 
twelve elementary text-books on ‘ Heat’ taken at random from a shelf, not one 
mentions the existence of such a machine as the steam-engine. 
This result is avoided if the course starts from a machine and is then left to 
create itself under the direction of the teacher. Suggestion and discussion at 
the end of a period as to the next thing to ‘go for’ result in some questions 
being simply answered, some discarded by consent for various reasons, whilst 
ae are dealt with experimentally by the boys themselves or by demonstration 
ectures. 
Thus the properties of water can be investigated as so many geological, 
biological, chemical, and physical ‘subjects.’ Or they can be correlated into 
one problem course beginning, for instance, with the hydraulic press and then 
developed as above. Starting from the press, there immediately arise trans- 
mission of pressure, fluids and solids, principles of machines, work and force. 
Various pumps follow, leading directly to air pressure and experimental 
investigation into it by the boys themselves. Barometers, pressure on divers, 
dams, lock-gates, together with deep-sea sounding, chalk, sand, clay, and 
Artesian wells provide the humanising element. Flotation follows with Archi- 
medes’ Principle, buoyancy, &c.; where there is a school bathing-place it is 
best worked out there practically with a raft, a raft of casks, and a weighing 
machine. 
Sea-water’s buoyancy leads on to its properties, solution of solids, crystallisa- 
tion and solution—all arising out of the problem, instead of as pointless and 
seemingly useless preliminaries necessary for some future unknown work of 
which the boy is ignorant. Solution of air and its influence on fish, &c., lead to 
Harrogate water, soda-water, sparkling wines, bread or sugar in a lemon squash. 
Carbon dioxide suggests its preparation and properties, respiration, breath- 
ing, burning, and decay, and so nitrates and manures on the one hand, and 
limestone, with limestone caverns, stalactites, hard and soft water, water supply, 
good and bad water on the other. Organic matter in water and its purification 
can extend as far into typhoid, diphtheria, bacteria, infection, inoculation, 
vaccination, milk, &c., as the teacher desires. a5 
The compounds and mixtures reached as above lead to inquiries as to the 
naturé of water and suitable chemical investigations, which are followed 
naturally by more physical considerations—its change of volume on becoming 
