382 
NATRORE 
| FEBRUARY 14, 1907 
that their very .success emphasises the defectiveness of 
the present condition of things in regard to higher technical 
training. This condition is due to the difficulty of securing 
attendance at day courses in our many excellent institu- 
tions. There has been some improvement in this respect, 
but the number of students taking systematic higher courses 
is lamentably small. Sir Horace Plunkett is convinced that 
the tendency to bring the instruction in the evening tech- 
nical institutes into the closest relationship with industrial 
requirements will go far to secure what is admittedly one 
of the most important desiderata to-day—the cooperation 
of employers and workers. It must be frankly recognised 
that the raison d’étre of the evening technical school is 
industrial efficiency, that the apprenticeship system under 
modern industrial conditions must fail to educate the young 
worker effectively, and that the evening technical school 
must now undertake some of the teaching previously con- 
ferred in the workshop. The great usefulness of American 
technical institutions is due in a large measure to the in- 
dividual interest taken in the students, not only during 
their attendance at the school, but during their subsequent 
career. The following papers were read and discussed :— 
The cooperation of adjacent authorities in the supply of 
higher technical education, -by Principal A. F. Hogg, of 
West Ham, and monotechnic ‘institutions, by Mr. Charles 
Harrap, of the St. Bride Foundation Institute, London. 
SOCIETIES AND ACADEMIES. 
LONDON. 
Royal Society, November 1, 1906.—‘‘The Nitrifi- 
cation of Sewage.’’ By Dr. G. Reid. Communicated by 
Prof. Gotch, F.R.S. 
The author gives an account of certain observations he 
recently made which point to the conclusion that by using 
fine-grain filter particles the depth of percolating filters 
may be greatly reduced. A filter composed of j-inch 
medium, which had been in constant use for three years, 
was tapped at four depths in such a way that samples 
could be collected to show the degree of purification effected 
at 1-foot intervals downwards, and the conclusions arrived 
at are based upon the analysis of numerous samples 
collected during a period of about twelve months, the de- 
livery to the filter being constant throughout and at a 
rate of 200 gallons per superficial yard. As regards the 
organic matter, both in suspension and solution in the 
septic tank effluent applied to the filter, the author found 
that the work of purification was effected at a depth of 
1 foot from the surface, leaving very little work for the 
deeper layers to accomplish. 
The following are the means of the more important 
figures of analyses :— 
Parts per 100,000 
Septic | 2. | oft Key |) Alt 
Tank | 5 so il) 3 tke ane 
Solids in Suspension | 7°60 | 0°25 | 0'09 | O'14 |! O'0O 
Free Ammonia 1°716 | 0'036 | 07020 0-009 0043 
Albuminoid Ammonia | 0°340 | 0°052 | 0°037 | 0°03I | 0°027 
Oxygen absorbed in | 
4 hours at 80°F. ... | 2"184 | 0°328 | 0°286  0°244 | 0°259 
Nitrous Nitrogen 0°000 | 0003 | 0'007 | 0°008 | 0°002 
Nitric Nitrogen 0700 | 2°07 | 1°99 | 1°85 | 1°99 
As regards the carbonaceous matter, the oxidation 
appeared to be equally rapid, for not only did the reduc- 
tion in oxygen absorbed reach practically its maximum at 
1 foot depth, but the air collected from the filter at 
different depths gave the following amounts of CO, per 
1000 :—1 foot, 19-5; 2 feet, 21-5; 3 feet, 20-0; 4 feet, 20-0. 
As regards the suspended organic solids, they are prac- 
tically all retained within the first foot, where liquefaction 
is effected (it is suggested by aérobic organisms). In 
confirmation of this, the following mean figures of per- 
centage loss on ignition of filter particles taken from 
different depths are given :—6 inches, 3:25; 1 foot, 0-99; 
2 feet. 0-65; 3 feet, 0-53; 4 feet, 0-53. 
NO. 1946, VOL. 75 | 
As regards the remarkable increase in the free ammonia 
in the samples from the lowest tray, it is suggested that 
the circumstance may be accounted for by a revival of 
anaérobic changes, the result of the asphyxiating effect of 
the products of combustion produced above. 
Anthropological Institute, January 22.— Annual General 
meeting.—-Prof. W. Gowland, president, in the chair.— 
Address on the dolmens and burial mounds of the early 
emperors of Japan: the President. It is extremely prob- 
able that the Japanese obtained the idea of raising mounds 
from the Chinese, the earliest burial mound in China 
dating from 1848 B.c. Little is known about the 
earliest Japanese mounds, but the later ones are always 
more or less large, and invariably contain either a sarco- 
phagus or dolmen. ‘There is an extremely large number 
of these mounds in japan, and Prof. Gowland himself 
examined 406. It is of interest to note that the dolmens 
are always near the coast or in the basins of the larger 
rivers, which points to the fact that at the time of their 
erection the Japanese only occupied these districts, the 
other parts of the country being inhabited by the primitive 
aborigines—the <Ainu. The distribution of the early 
Imperial mounds is also of importance historically. They 
ere found in four districts, which goes to prove that at 
an early date the country had no central Government, but 
that there were at least four independent tribes, each 
pecupying one of the districts where the large Imperial 
mounds are found. The date of these mounds is between 
the second century B.c. and the fifth or sixth of our era. 
As to the mounds themselves, the Imperial ones are 
double, with a conical peak at one end. ‘They are all of 
very great size, and are terraced and moated. In plan 
they are seen to be a combination of the square and 
circular varieties, but whether this has any significance 
is noc known. One interesting feature is that round each 
terrace a series of terra-cotta tubes—‘* Haniwa ’’—about 
18 inches high and 15 inches broad, are set in rows. They 
may have been placed there for structural reasons, or they 
may represent the wives, attendants, &c., who formerly 
were buried with the emperor. This practice was dis- 
continued in 2 B.c., and by an Imperial decree terra-cotta 
figures were substituted for the human victims. Many of 
these figures have been found, and in some cases they 
terminate in a ‘‘ Haniwa.’’ The largest of the Imperial 
mounds are in the central provinces; the largest of all is 
2000 feet long, and covers approximately an area of eighty- 
four acres. The interment is always in the conical peak 
of the circular part of the mounds. They are, as a rule, 
entirely artificial, but occasionally a natural eminence has 
been turned to account. 
Physical Society, January 25.—Prof. J. Perry, F.R.S., 
president, in the chair.—The strength and behaviour of 
brittle materials under combined stress: W. A. Scoble. 
The results described in the paper are a continuation of a 
series obtained from tests on a ductile material. The bars 
were of cast iron, 32-inch diameter, 30 inches between 
the bending supports, subjected to bending and twisting 
to fracture. The maximum principal stress and the maxi- 
mum shear, calculated on the assumption that there was 
no yield, each varied about 40 per cent. Plotting the 
corresponding bending and twisting moments, the points 
lie on an ellipse, the twisting moment being about 3000 Ib. 
inches, and the bending moment 2200 lb. inches at frac- 
ture. In all cases, except that of simple bending, the 
fracture was a spiral, completed by a part making a small 
angle with the axis and invariably coming under the 
knife -edge.—Recent improvements in spectrophotometers : 
F. Twyman. The paper deals with a form of Hifner 
spectrophotometer designed in 1904, and consists of two 
parts :—(A) The evaluation of the errors due to the polar- 
isation produced by the dispersion-prism and by the 
Hifner rhomb which brings about the accurate juxta- 
position of the two beams of light the intensities of which 
are to be compared; and the method by which in the 
recently constructed instruments it is arranged for these 
effects to neutralise one another. (B) The use of the 
instrument as a spectropolarimeter by placing in the space 
between the dispersion-prism and the second Nicol the 
media the optical rotations of which it is required to 
| measure. 
