The sun. [volume] (New York [N.Y.]) 1833-1916, 1899-09-03
NOTES ON SCIENCE AND IyDUsrnE

NOTES ON SCIENCE AND INDUSTRE 5
In recent address before the Royal Institute Of
Architects OF Ireland Sir Charles Cameron not only
expressed his doubts OF the commonly assumed me-
cessty for sewer ventilation-based upon the hypo-
thotical risk Of the air gases, thsy are
termed. attaining sufficient pressure 10 force the
traps of house drains connected with the sewer
but proposed system of ventilation IS substitute
for the aspiring shafts. Experiments had been
made, said the lecturer to ascertain whether mas
pressure actually exists in but he had never
been ablo TO determine the fact beyond tho most
trifnR amount when al tho vontilators on conaid-
cradle lengths Of main sewers were closed. A new
means OF ventilation is proposed, seemingly ado.
quate to meet the necessities Of the case-one which
depends upon the principle of tho diffusion OF gases
through porous materials certain pottery manu-.
faoturers making the apparatus required, which 10
in the form of cylinders inserted in the crown Of
the sewer. arrangement which, 1t is claimed. Of.
fectually bars the passage Of the microbc.
There has lately been installed on the cars Of the
Louvre Saint Cloud line Paris. low pressure acety.
ltne lighting system, novel plan. The vehicles,
while built under the form OF an omnibus. really
street cars. running as they do on tracks and
also provided with an Imperial or second story.
In this case. however, the material which generates
the gas not ordinary calcium carbide. but IL what
Letane and ssrroliet; this substance Is calcium
bide treated with glucose after i'm Of
eral weeks in petroleum. thus preventing an over
production OF gas. The generator is placed on the
platform of the under the stairs which lead into
the imperial. 10 Of form, being also simple and
oective after being generated, the ia dried and
the impurities are removed. Lead pipes conduct the
gas to the burners, which inclosed in globes
somewhat similar to those used for the well-known
Pintsch light there are two in the proper; one
tho imperial and one the platform. as we'll
small signal light of hve-candle power. The total
expense for the Ave lights is stated to be about fouH
cents Per hour. which is much cheaper than an
equivalent amount Of electric light.
An important point affecting the present manufaoS
turo oflooomoves in Great Britain is remarked upoH
by . writer in the Engineering Magazine. and which
exhibits the superiority Of the American system Of
building. The point in question is that, in the CASE
of the latter. the engine Is designed with very
large margin of power. Thus, IL an express engine
is designed to take 2Oo-ton load at hfty miles pei
hour. and the load should DO increased to 500 tons,
the locomotive is expected to take along and stil1
make time; again. II American express Is late. tho
engine runner Is expected to make UP the time lost,
even though the load be heavier than usual. On the
other hand, II an English engine is coupled to q
train containing . single car over the proscribs4
load, the driver insists pilot and gets It. and tha
same conditions obtain should the weather be bad
the rails slippery, or strong side wind likely to ID
encountered. In defence. however. OF the smaller
range Of power given tho English locomotive. It ia
argued that engine 10 certainly economical.
ly operated at about its full power, than II IL In
dragging about on the level dead weight represent
ing reserve power which may be required on heavy
grades be useful in the mt Of overload,
An Austrian chemist. whose name does not ap,
pear, has brought forward device for conveying
liquid air, the claim being that. In Its adaptabity
for this purpose, 1t 10 an improvement upon al
others especially in preventing evaporation. The
fluid very volatile and readily absorbs heat from
tho walls OF tho vessel which contains IL and
from the surrounding atmosphere. Heretofore.
tho plan has been to construct globulaR
| vessel with double walls q half-inch or more
apart except at the mouth, where they come
together; from the intervening space. air tight,
air being carefully exhausted; the vacuum prevent
ing absorption Of heat from outside. and acting
insulator-a little warmth, however. being able to
| penetrate, evaporation thus occurring. The linz
provement upon this consists In providing coatin q
of silver amAlgam tho inner surface of the outer
wall. this coating serving reflector for any heat
rays that may fall upon the vessel from outside.
In shape this flask is that of two placed base
to base Like the elobular holder. II must DO sup
| ported . ring standard.
For the purpose. in especial of photographing the
now planet Eros" on its expected approach to the
earth again next year. the astronomical department
OF Harvard University has in process Of construction
remarkable telescope likely, 1t Is thought. to give
results of great value to astronomy. II the instru-
| ment Is mounted in favorable position Though II
| will have an aperture Of only twelve to fourteen
inches Its focal leneth-a most remarkable feature
will be 1875 1872 feetthe position to be horizontal
and the star reflected into II by Of o mirror.
tho earths motion to be counteracted BY moving the
| Photographic plate by clockwork. Thus Is largo
horizontal photo Photograph. antcipations Of its pc.
culiar adAptness entertained In the work Of photo
graphing the hne details Of the suns surface whom
collapsed, May 20. 1900. Theimages Of the moon. too.
obtained with such telescope would be more than q
foot in diameter and. even II printed without
larRement would probably surpass the best photo
graphs yet taken.
The latest device in the way of Ife.saving sp-
parAtus appears to be due to the ingenuity Of e 8.
Norris London inv its application to render
| ing boats unsuitable having been successfully
proved by trials made ct St. Ketherne's Docks. Lon
don. If the invention is to be applied to a life boat
already fitted with water-tght compartments. those
spaces filled With indefinite number OF closed
tubes, each few inches long and made of some
strong impervious material like waterproof paper.
| But Q boat with such compartments Is not neces.
| sary, tho little can DO held in canvas band
nailed along tho sides of any ordinary rowboat and
| render II quite unsuitable. The principle can also
| be applied to nfe-belts and buoys-replacing the
tho cork ordinarily used-and with much loss cost.
For removing the ncrustation Of boilers. a French
engineer. M. savreaux, now announces an improved
method. According to this. after extinGuishing the
fires the boiler water blown of very gradually at the
Same time admitting an equal volume Of cold water
that the water gauge shows change OF level Al
| soon as tho water has In this manner been suf
ncsntly cooled down. 1t is suddenly blown OF; 1t ID
this latter operation which removes the major par
of any incrustation which may be present what re-
mains being very easily detached by scrapinZ It Il
necessary, however. that the cleaning OF the boiler
be taken In hand Immediately upon completion Of
the blowing-on operation. otherwise tho furatonG
will harden and adhere again TO the boiler plAtes.