be hardly felt, and would make no one the V; 
poorer; while the growing generation would 
be profited beyond all calculation. ' 
Never fear that a large library hi the a 
school would conduce to little study and 
poor lessons. We believe a contrary result 
would universally ensue. Such at least might 
be insured by proper management. Make 
the privilege of the library dependent on 
USEFUL AND SCIENTIFIC NOTES, 
outside, and fifteen feet high. The sides arc 
wedge-shaped, the lower edge being eight 
inches, and the upper something over eight 
feet, in thickness, and the roof resting on 
these sides is five feet thick, lea ing a work¬ 
ing-chamber nine feet in height All the 
timbers are bolted together with one and a- 
qnarter inch bolts, varying from two to seven 
feet in length, and the structure is made as 
crmtific anh tlsrfnl 
uaitiomrl 
Spots on the Sun ,—The Washington Re¬ 
publican says that the astronomers are just 
now turning their glasses in the direction of 
the sun, that luminary having lately broken 
out iu a perfect rash of spots, some of them 
of enormous size. No less than eight groups 
of spots are visible, and of these groups four 
SCHOOL LIBRARIES, 
THE EAST RIVER BRIDGE, 
School authorities err greatly, we think, 
in malting such meager provision for the 
literary longings of scholars. Libraries for 
This erreat suspension bridge, a plan of 
which we herewith reproduce from the 
Manufacturer and Builder, is designed to 
N.Y0RK. 
NOW IN PROCESS OJB’ COxNSTltUCTION, 
common schools are generally most paltry 
affairs. We know of few Avhich hold out 
any inducement for the class they are sup¬ 
posed to gratily and profit. They wore pro¬ 
cured, as a general thing, in a day to which 
the memory of the oldest trustee runneth 
not back; there has never been any addi¬ 
tion thereto, since. Of live, entertaining 
literature they contain scarcely a specimen. 
Beyond the " Tales of a Grandfather;’ some 
ol “ Sparks’ Histories” and kindred works, 
they very rarely go. The sum total is coin- 
firm ns possible in every way. 
Six shafts, lined with boiler iron, pass 
through the root of the caisson, iu which the 
water therein collected will rise to the height 
of the tide outside. Two other shafts will 
allow the passage of workmen, and the re¬ 
moval of earth from within. Air-pumps will 
force air into the caisson through air-shafts, 
expelling the water, and enabling laborers to 
work upou the bottom. As fast as these ex¬ 
cavate the earth they will deposit it around 
the shafts, through which a dredging ma¬ 
chine will lift it and dump it into scows. 
When this mammoth affair shall bo sunk 
to its desired position, thirty feet below low- 
tide, additional courses of timber will be laid 
on top of it, to the height of fifteen feet, and 
filled in with concrete; and when the whole 
has become firmly fixed la place, the tower 
will be built on the solid foundation thus se¬ 
cured. On the New York side it is believed 
nothing of the kind will be necessary, the 
nature of the shore there being wholly dif¬ 
ferent. 
That the bridge when completed will he 
well secured seems certain. Each of the 
four cables will enter the anchor walls to a 
distance of twenty feet, and will there con¬ 
nect with the anchor-chaius composed of ten 
links, each twelve feet or more in length, 
and forming a downward curve of a quarter 
of a circle, in order to convert a portion of 
the tension into downward pressure. Then 
the cables will not be compelled to support 
the entire weight of the bridge. Stays, run¬ 
ning from the top of each pier to the bottom 
of the span, will relieve much of the strain— 
indeed, Mr. Roebling asserts that the bridge 
would not fall if the cables were removed, 
would only sag. 
Those who considered the first suspension 
bridge ever built as a very pretty but fragile 
effect closer communication between the two 
great cities of New York and Brooklyn. In 
conception it is grander than anything of the 
kind previously dreamed of, and its success¬ 
ful accomplishment will prove one of the 
proudest engineering triumphs the world has 
ever witnessed. The late John A. Roebling, 
who constructed the Niagara and Cincinnati 
suspension bridges, originated the design, ancl 
its execution is entrusted to his son. 
As shown in our engraving, the bridge is 
to be supported by four cables, resting on 
two piers situated on the shores. These 
piers arc to be 1,020 feet apart, and two hun¬ 
dred and eighty feet high, and the bridge- 
bed will rest one hundred and thirty feet 
above tide-water, thus offering no impedi¬ 
ment to navigation. The cables will consist 
of parallel steel wire, and " ill he nearly one 
foot in thickness. They will be anchored in 
solid masonry, 1,337 feet from the pier on 
the New York side, and eight hundred and 
thirty seven feet, from that, on the Brooklyn 
side. Thus 1 he real span will be 3,704 feet 
in length; and the approaches beyond these 
points will be of arched masoury, thrown, 
like the half-spans between anchorage and 
piers, over streets and houses. These ap¬ 
proaches will commence at the City Hal) 
Park, iu New York, and at the junction of 
Fulton and Sands streets, in Brooklyn, and 
although rising but three and a-half feet to 
one hundred, will offer small obstruction to 
street-travel. 
Naturally, the piers must be capable of 
withstanding an immense strain. Their 
base at water-line is to be one hundred and 
thirty-four feet long by fifty-six feet wide, 
and the heaviest masonry is to be employed 
in their construction. Each will contain 
over 9U0,U00 cubic feet of granite, and will 
weigh over 70,000 tons. In each pier there 
will be two arches, for entrances 
to the bridge, and each arch-way 
will be thirty-two feet wide, 
giving passage to a railroad 
track, a carriage-way and a side¬ 
walk. The bridge will weigh 
3,600 tons, and it is thought this 
will be increased by transitory 
weight of trains, carriages, 
horses, etc., to little less than 
5,000 tons. To insure complete 
safety, therefore, the foundation 
of each pier will number 17,000 
square feet of surface, upon 
which the pressure will be only 
about four tons per square foot, 
A proper foundation for these 
massive piers is of the greatest 
moment. Labor upon the Brook¬ 
lyn side was begun in January 
last, and has since been con¬ 
tinued, dredging machines being 
employed preparatory to sink¬ 
ing the colossal caisson which 
has been built at Greenpoint, a 
cross-section of winch is shown 
below. T1 1 is will bo floated into 
position at high tide. The cais¬ 
son, necessary because the Brooklyn shore 
presents no rock-basis, i3 constructed of 
white pine timbers a foot square, the 
seams tarred to render them water¬ 
tight, and a sheathing of tin between 
two of felt placed between the outside lay¬ 
ers of timber to make the whole air-tight. 
It is one hundred and sixty-eight feet long 
by one hundred and two feet wide on the 
are to be seen in the sun’s northern hemis¬ 
phere, two in the equatorial region, and two 
in his southern hemisphere. The largest 
single spot covers a superficial area of not 
Ies3 than one thousand four hundred and 
fifty-eight millions of square miles, or seven 
times the superficies of the terraqueous globe. 
The northern hemisphere of the Bun pre¬ 
sented on the (Hli of February a most re¬ 
markable linear series of six groups of spots, 
parallel with his equator, each group sep¬ 
arated by about the average length of one 
group from the next in order, and the whole 
forming a chain of apparently connected 
phenomena not less than four hundred thou¬ 
sand miles iu length. It is thought that 
these phenomena may he followed by some 
such remarkable auroral «-s were 
noticed iu 1856, seeing that these displays 
seem to be not unfrequcutly dependent upon 
the appearance of these spots upon the sun. 
Testing Blood Stains—A chemist in Aus¬ 
tralia has made au important discovery, u 
new test for blood staius, which is very deli¬ 
cate and sure. It consists iu the application 
of tincture guuiaeum and oxidized ether 
(peroxide of hydrogen dissolved in ether) to 
the stain, when it turns to a beautiful blue. 
Even in the case of a blood stain twenty 
years old, the test showed the same result. 
This is regarded by scientific men as a very 
valuable discovery. 
The Ocean Bottom .—A large part of the 
mud at the bottom of the deep ocean consists 
of microscopically small, rounded particles 
of carbonate of lime aggregated together. 
They arc called globerigitUR, and formed by a 
jelly-like animal, without organs of any sort, 
but which moves by thrusting out portions 
of its body, which act as arms or legs. There 
arc also sponge spicules and Hint skeletons 
good scholarship, and there would lie no 
trouble. In fact a new impetus would there¬ 
by be given to study, and the average schol¬ 
arship would rank several grades higher. 
There is too little thought given to this mat¬ 
ter, Sunday-school libraries are improving 
in character and completeness; why should 
not the common school libraries be corre¬ 
spondingly improved? The one does not 
render the other less necessary. Both are 
essentials. A knowledge of general litera¬ 
ture is now-a-dnys imperatively demanded, 
and every aid to its acquirement should, lie 
granted. Ab educators, we should properly 
consider the situation, and then take meas¬ 
ures accordingly. 
CHANGING TEXT-BOOKS, 
A convention of school-book publishers 
was recently held in this (New York) city, 
for the purpose of harmonizing the trade in 
which they are engaged. Us action will 
doubtless result in the furtherance of a mu¬ 
tual interest. As we understand it, there is 
to be no more conflict between rival houses, 
—no more giving away of competing text¬ 
books to insure their introduction iu schools 
here and there. Agents are to bn dispensed 
with, other than local, and the business is to 
be henceforth carried on in a purely legiti¬ 
mate way, and so as to result In profit rather 
than loss. 
All this is well. A reform in this portion 
of the publishing trade had become a vital 
necessity. School-book publishers were 
nearly ruining themselves, and for their own 
welfare a new system was demanded. For 
the welfare of schools, also, a change was as 
surely needed. The war of the publishers 
was felt in almost every school-house in the 
land. Changes in text-books, brought about 
thereby, were far too frequent, 
and very damaging. 
That some benefit to the 
schools, as well as the publish¬ 
ers, will grow out of the late 
convention, we arc fain to be¬ 
lieve. If text-books are no 
longer to be given away, to in¬ 
sure their use, one motive for 
these continual changes will 
cease to exist. Other motives 
should in a great measure be 
ignored. The only motive that 
should obtain iu the mind of any 
teacher or commissioner should 
be a certain book’s, or series’, 
absolute superiority over every 
other book or series. This ab¬ 
solute superiority is not easily 
determined on; and until it 
is fully established beware of 
changes! The sums which 
have been spent, within the last 
decade, in introducing new 
text-books throughout the coun¬ 
try would build a new sebool- 
house in every needy district. 
As a result of this vast ex¬ 
penditure we have a motley collection of 
books in a majority of schools, and a poorer 
average grade of scholarship in all. Now 
that the publishers have held a convention 
to subserve their interests in the matter of 
text-hooks, would it not be a good idea for 
teachers, commissioners and trustees to hold 
a convention to subserve the interests of 
schools ? Great good might be effected. 
rsc:nw srutoc 
NN5R WATER 
W, UZBTR.n 
look with wonder upon this latest success of the water when alive. The same structure 
the engineer’s skill when it shall link two characterizes chalk, and the mud of the sea 
cities together; and admirers of mechanical bottom dries into a substance resembling 
genius everywhere may well exult over chalk; so that we may say chalk is stil 
American boldness and energy as here ex- forming wherever there is a temperature a 
hibited. In the light of such accomplish- the bottom or 45° or more. We also judge 
meuts, we may well marvel over the proba- 'hat the chalk of Europe was once at the 
blc grandeur of the future, bottom of a deep sea. 
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