Vol. XXIV. No. 7.] 
POPULAR SCIENCE INEWS. 
101 
little lower than the one before it; and in this way 
the fine powder is separated from the coarser. Pipe- 
clay is then added to it, and enough water to make 
a paste about as thick as cream, and this is ground 
until the substances are perfectly mixed. For hard 
pencils, more clay is added ; for soft ones, less ; 
medium liard pencils contain about seven parts 
of clav to ten of graphite. After grinding, the 
paste is put into canvas bags and pressed until all 
the water runs out, leaving a thick dough. This 
dough is then put into an iron cylinder with a tight- 
fitting pi^ton. In the bottom of the cylinder are 
holes the size and shape of the lead desired, and 
through those the dough is slowly forced by the 
descending piston, coming out in long strips. 
These strips are then cut into the proper lyngths, 
baked, and put into their wooden cases. 
The third or amorphous form is represented by 
charcoal. Charcoal is made by burning wood in a 
liiiiiti'd supply of air. Sticks of wocmI are piled up 
into a round heap, with a small hole in the centre 
for a chimney. Another hole runs from the chim- 
ni'v to the outside of the pile, so as to give a draft. 
The whole pile is then covered with sod and earth. 
The wood is lighted through the chimney, and 
chars- slowly until it is all converted to charcoal. 
The time required varies from one to three weeks, 
according to the size of the pile. The best quality 
of charcoal is made by heating wood in iron cylin- 
ders. When made in this way, some other valuable 
substances — as wood-alcohol, etc. — are also formed, 
which run off as liquids and are collected. This 
kind of charcoal is used for gunpowder. Charcoal 
is black, lustreless, soft, and smutty. It has no 
crvstalline form, but retains the internal and exter- 
nal forms ol the tree from which it is made. While 
the wood in the pits is charring, the walls of the 
wood-cells become charcoal, but the matter within 
the cells is dris'en olT. This makes the charcoal 
very porous, and it absorbs air to such an extent as 
to float on water. Charcoal has a strong tendency 
to condense gases on its surface. It acts on different 
gases to different degrees, but most readily on 
ammonia and sulphuretted hydrogen. It is also 
Hsed to absorb coloring matter in bleaching colored 
>(>lulions; but bone-black — a sort of charcoal made 
l)V burning animal bones — is better for this purpose, 
lirown sugar is turned into white sugar by running 
it through a layer of bone-black from twenty to 
thirty feet high. 
Lamp-black is made in much the same way as 
charcoal, only no wood is used. Heavy oil of tar 
or natural gas is burned in a close chamber, at the 
lop of which is a tight-fitting iron dome. The oil 
is lighted, and burns with a smoky flame, giving 
iiiY small particles of carbon, which are condensed 
on the sides of the chamber into lamp-black. 
When th* process is finished, the dome descends 
and scrapes the lamp-black off. It is tolerably pure, 
is very black and permanent, and can be advan- 
tageously used in making paint, blacking, etc. 
The question may sometimes arise : How do we 
know that these allotropic forms are really earbon ? 
The proof is, if we burn twelve parts of carbon it 
will f^Jve forty-four parts of carbonic acid gas — and 
this is the case with each of the three forms. 
HOW THE BURMESE WORK THEIR OIL 
WELLS. 
Dr. Nokti.in<;, of the Indian Geological Survey, 
to whose report on the petroleum deposits of Bur- 
niah reference has already been made, gives an 
interesting description of the native method of dig- 
ging the wells. As soon as a native has made up 
his mind where he is going to have a new well, the 
workmen, usually four in number, begin to dig a 
Square shaft, the sides of which measure between 
four feet and four feet six inches. Over this pit a 
cross beam, supported on stanchions at either side, 
is placed, in the centre of which is a small wooden 
drum, or cylinder, which, with its axis, is made of a 
single piece of wood, the latter running on coarse 
fork-shaped supports. The leather rope used in 
hauling up the oil passes over the drum, and on it is 
fastened the workman who is going to be lowered 
down, as well as the common earthenware pot in 
which the oil is drawn up. If possible, the well is 
so placed that the men or women drawing the rope 
walk down an inclined plane along the slope of a 
hill. The tools employed in digging are quite 
primitive, and can only be used in soft strata. 
Timber is used to support the walls of the shaft, 
and the latter is lined with wood. This wooden 
wall has considerable strength, but it has to be 
carefully watched lest it should give way. 
The workmen are lowered in an ingenious way. 
The man sits on two slings formed of strong rope 
running between his legs and knotted over his left 
shoulder. To prevent sliding, a thin rope runs 
down from the knot, across the breast, underneath 
the right shoulder to the back, where it is fastened 
to the rope forming the slings. A second rope for 
the same i>urpo.se is fastened round the hips. On 
account of the explosive gas filling the shaft, no 
light can be taken down; the workman, therefore, 
tics up his eyes previously to descending, so as to 
enable him to see during the short time he is in the 
well, otherwise it would take him longer to accustom 
his eyes to the darkness than he is able to stay down 
on account of the gas, which renders breathing dif- 
ficult. The data obtained by Dr. Noetling as to the 
time occupied in the ascent and descent, and the 
period during which the laborer can remain below, 
show that not twenty-five per cer\t. of the total 
working time is really spent in extracting the oil. 
Two hundred and ninety seconds is the longest 
time any man, however strong, can remain below 
without becoming unconscious, while in some he 
can only remain sixty seconds. With increasing 
depths the difficulties in obtaining the oil after the 
Burmese methods become insuperable. Hence the 
limit is 310 feet, and the workers object to more 
than J50 feet. 
The drawing up of the oil is as primitive as 
everything else. The rope is fastened round the 
neck of the ball-shaped pot, and, being lowered, is 
allowed to fill by sinking in the oil below. The oil 
thus raised is poured into another pot of the .same 
shape, but much larger, and twelve of these are 
packed on each country cart. — London Times. 
TiiK SiiiKKiAN R.MLWAY. — The Russian Gazette 
of St. I'etershiiry states thi-it the special commission 
has just drawn up its report on the most practicable 
way of constructing the -great Siberian railway. 
According to this report the work should be accom- 
plished step by step, but with the result that the 
whole line should be completed in 1900. The cost 
of construction would not exceed 250,000,000 
roubles, spread over ten years, so that the treasury 
would only have to advance 25,000,000 roubles a 
year. Judicious economy would reduce this sum 
by 50,000,000 roubles, so that the cost per verst 
would not exceed from 25,000 to 28,000 roubles. 
The line would be as narrow as possible; conduits 
excepted, all the work would be in wood; and^arge 
stations would only be established at the most 
important points. . At the beginning of the enter- 
prise, also, there would be a minimum of rolling 
stock. For this reason engines of eight wheels 
would be employed, except in the steppes, where 
engines of six wheels might be adopted. Another 
suggestion is, that those sections most promising of 
revenue should be begun first. 
Tljc Out-Door morld. 
Edited by HARLAN H. BALLARD, 
Pre.sii)Ent of the Agassiz A.ssociation. 
[P. O. AdDUKSS, PlTTSFIELD, MASS.] 
To further introduce the News to the 
members of the Ao;as.siz Association, the 
proprietors offer a special ittducement for 
new siihscrihers. Any member sending 70 
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Co., 5 Somerset Street, Boston, will receive 
all tiie back numbers from January (six 
copies) and those to follow, to January, 1891. 
The complete numbers from January are 
limited ; tliercfore sentl 3'our name at once. 
A STATE CONVENTION. 
■SUCCESSFUL MEETING OF THE NEW JKKSEY 
ASSE.MnLY. 
The Semi-annual Convention of the New 
Jersey State Assembly was held at Newark, 
May 10, in the High School. Eighteen 
Chapters were represented. A delegation 
of New York Chapters was present. The 
morning session was devoted to business. 
The A. A. "Hill and Dale Club" held a 
meeting at noon. 
During the recess, the visiting delegates were 
entertained by Professor Sonn and other members 
of the Newark Chapter. The new polariscope at 
the High School was much admired, and the polari- 
scopic slides made by the students highly praised. 
The solar lantern was called into service to show a 
number of the slides which are the property of the 
Newark Chapter. 
At the afternoon meeting, one hour was devoted 
to the consideration of questions which had been 
dropped into a question-box. Then followed an 
address by President Lighthipe, of Woodbridge, 
upon the clays and marls of New Jersey. The 
lecture was illustrated with maps and drawings, 
.md closed with a cordial invitation for Agassiz 
members to join in the Hill and Dale Club excur- 
sions to the clay beds near Amboy on the 6th 
of June, and to the marl pits at Farmingdale on 
May 30. Messrs. Herman Lehlbach and William 
Kinsey, members of the local Chapter, then fol- 
lowed with an illustrated practical talk upon " What 
Can Be Done in the Lecture-Room with a Tin 
Can." The young men had prepared twelve inter- 
esting and very instructive experiments in physics, 
which they performed entirely with tin cans of vary- 
ing sizes. Their eftbrts were enthusiastically re- 
ceived. Mr. Charles Teeter then gave a series 
of six chemical experiments, which were designed 
to explain some of the tricks usually offered bv 
magicians. Mr. Kelly, of Elizabeth, then read a 
paper upon the basaltic formations of America and 
Europe. His article was illustrated by photographs 
and lantern slides. The session closed with a lec- 
ture upon "Certain Sound Phenomena," delivered 
by Professor Sonn, with apparatus prepared largely 
for the occasion by himself and members of the 
Edison section of the Agassiz Chapter connected 
with the school. 
The display of minerals, phosphates, and curios 
presented by these members of "351, B" is greatly 
to be commended. Particularly noticeable in the 
displ.iy were three large rattlesnake skins with 
rattles, a collection of Brazilian iridescent beetles, 
and Bergen cut minerals. A paper upon the last- 
