were located on the moraine of the Green Bay glacier, is that their
home, in case they had a common one, is between the northeastern
corner of the State of Wisconsin and the eastern summit of the ice
mantle--a narrow strip of country of great extent, but yet a first
approximation of the greatest value. If we assume, further, that the
Saukville, Burlington, and Dowagiac stones, which were found on the
moraine of the Lake Michigan glacier, have the same derivation, their
common home may confidently be placed as far to the northeast as
the wilderness beyond the Great Lakes, since the Green Bay and Lake
Michigan glaciers coalesced in that region. The small stones found at
Plum Creek, Wisconsin, and the Cincinnati stone, if the locations of
their discovery be taken into consideration, still further circumscribe
the diamond's home territory, since the lobes of the ice mass which
transported them made a complete junction with the Green Bay and Lake
Michigan lobes or glaciers considerably farther to the northward than
the point of union of the latter glaciers themselves.
[Illustration: THREE VIEWS OF A LEAD CAST OF THE MILFORD STONE (six
carats); enlarged about three diameters.
We are indebted to the courtesy of Prof. T. H. Norton, of the
University of Cincinnati, for the above illustrations.]
If, therefore, it is assumed that all the stones which have been found
have a common origin, the conclusion is inevitable that the ancestral
home must be in the wilderness of Canada between the points where the
several tracks marking their migrations converge upon one another, and
the former summit of the ice sheet. The broader the "fan" of their
distribution, the nearer to the latter must the point be located.
It is by no means improbable that when the barren territory about
Hudson Bay is thoroughly explored a region for profitable diamond
mining may be revealed, but in the meantime we may be sure that
individual stones will occasionally be found in the new American homes
into which they were imported long before the days of tariffs and ports
of entry. Mother Nature, not content with lavishing upon our favored
nation the boundless treasures locked up in her mountains, has robbed
the territory of our Canadian cousins of the rich soils which she has
unloaded upon our lake States, and of the diamonds with which she has
sowed them.
[Illustration: COMMON FORMS OF QUARTZ CRYSTALS.]
[Illustration: COMMON FORMS OF DIAMONDS. The African stones most
resemble the figure above at the left (octahedron). The Wisconsin
stones most resemble the figure above at the right (dodecahedron).]
The range of the present distribution of the diamonds, while perhaps
not limited exclusively to the "kettle moraine," will, as the events
have indicated, be in the main confined to it. This moraine, with
its numerous subordinate ranges marking halting places in the final
retreat of the ice, has now been located with sufficient accuracy by
the geologists of the United States Geological Survey and others,
approximately as entered upon the accompanying map. Within the
territory of the United States the large number of observations of the
rock scorings makes it clear that the ice of each lobe or glacier moved
from the central portion toward the marginal moraines, which are here
indicated by dotted bands. In the wilderness of Canada the observations
have been rare, but the few data which have been gleaned are there
represented by arrows pointed in the direction of ice movement.
There is every encouragement for persons who reside in or near the
marginal moraines to search in them for the scattered jewels, which
may be easily identified and which have a large commercial as well as
scientific value.
The Wisconsin Geological and Natural History Survey is now interesting
itself in the problem of the diamonds, and has undertaken the task of
disseminating information bearing on the subject to the people who
reside near the "kettle moraine." With the co-operation of a number of
mineralogists who reside near this "diamond belt," it offers to make
examination of the supposed gem stones which may be collected.
The success of this undertaking will depend upon securing the
co-operation of the people of the morainal belt. Wherever gravel
ridges have there been opened in cuts it would be advisable to look
for diamonds. Children in particular, because of their keen eyes and
abundant leisure, should be encouraged to search for the clear stones.
The serious defect in this plan is that it trusts to inexperienced
persons to discover the buried diamonds which in the "rough" are
probably unlike anything that they have ever seen. The first result of
the search has been the collection of large numbers of quartz pebbles,
which are everywhere present but which are entirely valueless. There
are, however, some simple ways of distinguishing diamonds from quartz.
Diamonds never appear in thoroughly rounded forms like ordinary
pebbles, for they are too hard to be in the least degree worn by
contact with their neighbors in the gravel bed. Diamonds always show,
moreover, distinct forms of crystals, and these generally bear some
resemblance to one of the forms figured. They are never in the least
degree like crystals of quartz, which are, however, the ones most
frequently confounded with them. Most of the Wisconsin diamonds have
either twelve or forty-eight faces. Crystals of most minerals are
bounded by plane surfaces--that is to say, their faces are flat--the
diamond, however, is inclosed by distinctly curving surfaces.
The one property of the diamond, however, which makes it easy of
determination is its extraordinary hardness--greater than that of any
other mineral. Put in simple language, the hardness of a substance
may be described as its power to scratch other substances when drawn
across them under pressure. To compare the hardness of two substances
we should draw a sharp point of one across a surface of the other
under a pressure of the fingers, and note whether a permanent scratch
is left. The harder substances will always scratch the softer, and if
both have the same hardness they may be made to mutually scratch each
other. Since diamond, sapphire, and ruby are the only minerals which
are harder than emery they are the only ones which, when drawn across a
rough emery surface, will not receive a scratch. Any stone which will
not take a scratch from emery is a gem stone and of sufficient interest
to be referred to a competent mineralogist.
The dissemination of information regarding the lake diamonds through
the region of the moraine should serve the twofold purpose of
encouraging search for the buried stones and of discovering diamonds
in the little collections of "lucky stones" and local curios which
accumulate on the clock shelves of country farmhouses. When it is
considered that three of the largest diamonds thus far found in
the region remained for periods of seven, eight, and sixteen years
respectively in the hands of the farming population, it can hardly be
doubted that many other diamonds have been found and preserved as local
curiosities without their real nature being discovered.
If diamonds should be discovered in the moraines of eastern Ohio, of
western Pennsylvania, or of western New York, considerable light would
thereby be thrown upon the problem of locating the ancestral home. More
important than this, however, is the mapping of the Canadian wilderness
to the southeastward and eastward of James Bay, in order to determine
the direction of ice movement within the region, so that the _tracking_
of the stones already found may be carried nearer their home. The
Director of the Geological Survey of Canada is giving attention to this
matter, and has also suggested that a study be made of the material
found in association with the diamonds in the moraine, so that if
possible its source may be discovered.
With the discovery of new localities of these emigrant stones and the
collection of data regarding the movement of the ice over Canadian
territory, it will perhaps be possible the more accurately and
definitely to circumscribe their home country, and as its boundaries
are drawn closer and closer to pay this popular jewel a visit in its
ancestral home, there to learn what we so much desire to know regarding
its genesis and its life history.
* * * * *
William Pengelly related, in one of his letters to his wife from the
British Association, Oxford meeting, 1860, of Sedgwick's presidency
of the Geological Section, that his opening address was "most
characteristic, full of clever fun, most imperative that papers should
be as brief as possible--about ten minutes, he thought--he himself
amplifying marvelously." The next day Pengelly himself was about to
read his paper, when "dear old Sedgwick wished it compressed. I replied
that I would do what I could to please him, but did not know which to
follow, his precept or example. The roar of laughter was deafening. Old
Sedgwick took it capitally, and behaved much better in consequence."
On the third day Pengelly went to committee, where, he says, "I found
Sedgwick very cordial, took my address, and talks of paying me a
visit."
NEEDED IMPROVEMENTS IN THEATER SANITATION.
BY WILLIAM PAUL GERHARD, C. E.,
CONSULTING ENGINEER FOR SANITARY WORKS.
Buildings for the representation of theatrical plays must fulfill
three conditions: they must be (1) comfortable, (2) safe, and (3)
healthful. The last requirement, of _healthfulness_, embraces the
following conditions: plenty of pure air, freedom from draughts,
moderate warming in winter, suitable cooling in summer, freedom at
all times from dust, bad odors, and disease germs. In addition to the
requirements for the theater audience, due regard should be paid to the
comfort, healthfulness, and safety of the performers, stage hands, and
mechanics, who are required to spend more hours in the stage part of
the building than the playgoers.
It is no exaggeration to state that in the majority of theater
buildings disgracefully unsanitary conditions prevail. In the older
existing buildings especially sanitation and ventilation are sadly
neglected. The air of many theaters during a performance becomes
overheated and stuffy, pre-eminently so in the case of theaters where
illumination is effected by means of gaslights. At the end of a long
performance the air is often almost unbearably foul, causing headache,
nausea, and dizziness.
In ill-ventilated theaters a chilly air often blows into the auditorium
from the stage when the curtain is raised. This air movement is the
cause of colds to many persons in the audience, and it is otherwise
objectionable, for it carries with it noxious odors from the stage
or under stage, and in gas-lighted theaters this air is laden with
products of combustion from the footlights and other means of stage
illumination.
Attempts at ventilation are made by utilizing the heat due to the
numerous flames of the central chandelier over the auditorium, to
create an ascending draught, and thereby cause a removal of the
contaminated air, but seldom is provision made for the introduction
of fresh air from outdoors, hence the scheme of ventilation results
in failure. In other buildings, openings for the introduction of pure
air are provided under the seats or in the floor, but are often found
stuffed up with paper because the audience suffered from draughts. The
fear of draughts in a theater also leads to the closing of the few
possibly available outside windows and doors. The plan of a theater
building renders it almost impossible to provide outside windows,
therefore "air flushing" during the day can not be practiced. In the
case of the older theaters, which are located in the midst or rear of
other buildings, the nature of the site precludes a good arrangement of
the main fresh-air ducts for the auditorium.
Absence of fresh air is not the only sanitary defect of theater
buildings; there are many other defects and sources of air pollution.
In the parts devoted to the audience, the carpeted floors become
saturated with dirt and dust carried in by the playgoers, and with
expectorations from careless or untidy persons which in a mixed theater
audience are ever present. The dust likewise adheres to furniture,
plush seats, hangings, and decorations, and intermingled with it are
numerous minute floating organisms, and doubtless some germs of disease.
Behind the curtain a general lack of cleanliness exists--untidy actors'
toilet rooms, ill-drained cellars, defective sewerage, leaky drains,
foul water closets, and overcrowded and poorly located dressing rooms
into which no fresh air ever enters. The stage floor is covered with
dust; this is stirred up by the frequent scene shifting or by the
dancing of performers, and much of it is absorbed and retained by the
canvas scenery.
Under such conditions the state of health of both theater goers
and performers is bound to suffer. Many persons can testify from
personal experience to the ill effects incurred by spending a few
hours in a crowded and unventilated theater; yet the very fact that
the stay in such buildings is a brief one seems to render most people
indifferent, and complaints are seldom uttered. It really rests with
the theater-going public to enforce the much-needed improvements. As
long as they will flock to a theater on account of some attractive play
or "star actor," disregarding entirely the unsanitary condition of the
building, so long will the present notoriously bad conditions remain.
When the public does not call for reforms, theater managers and owners
of playhouses will not, as a rule, trouble themselves about the matter.
We have a right to demand theater buildings with less outward and
inside gorgeousness, but in which the paramount subjects of comfort,
safety, and health are diligently studied and generously provided
for. Let the general public but once show a determined preference for
sanitary conditions and surroundings in theaters and abandon visits to
ill-kept theaters, and I venture to predict that the necessary reforms
in sanitation will soon be introduced, at least in the better class
of playhouses. In the cheaper theaters, concert and amusement halls,
houses with "continuous" shows, variety theaters, etc., sanitation
is even more urgently required, and may be readily enforced by a few
visits and peremptory orders from the Health Board.
When, a year ago, the writer, in a paper on Theater Sanitation
presented at the annual meeting of the American Public Health
Association, stated that "chemical analyses show the air in the dress
circle and gallery of many a theater to be in the evening more foul
than the air of street sewers," the statement was received by some of
his critics with incredulity. Yet the fact is true of many theaters.
Taking the amount of carbonic acid in the air as an indication of its
contamination, and assuming that the organic vapors are in proportion
to the amount of carbonic acid (not including the CO_{2} due to the
products of illumination), we know that normal outdoor air contains
from 0.03 to 0.04 parts of CO_{2} per 100 parts of air, while a few
chemical analyses of the air in English theaters, quoted below, suffice
to prove how large the contamination sometimes is:
Strand Theater, 10 P. M., gallery 0.101 parts CO_{2} per 100.
Surrey Theater, 10 P. M., boxes 0.111 " " "
Surrey Theater, 12 P. M., boxes 0.218 " " "
Olympia Theater, 11.30 P. M., boxes 0.082 " " "
Olympia Theater, 11.55 P. M.., boxes 0.101 " " "
Victoria Theater, 10 P. M., boxes 0.126 " " "
Haymarket Theater, 11.30 P. M., dress circle 0.076 " " "
City of London Theater, 11.15 P. M., pit 0.252 " " "
Standard Theater, 11 P. M., pit 0.320 " " "
Theater Royal, Manchester, pit 0.2734 " " "
Grand Theater, Leeds, pit 0.150 " " "
Grand Theater, Leeds, upper circle 0.143 " " "
Grand Theater, balcony 0.142 " " "
Prince's Theater, Manchester 0.11-0.17 " "
(Analyses made by Drs. Smith, Bernays, and De Chaumont.)
Compare with these figures some analyses of the air of sewers. Dr.
Russell, of Glasgow, found the air of a well-ventilated and flushed
sewer to contain 0.051 vols. of CO_{2}. The late Prof. W. Ripley
Nichols conducted many careful experiments on the amount of carbonic
acid in the Boston sewers, and found the following averages, viz.,
0.087, 0.082, 0.115, 0.107, 0.08, or much less than the above analyses
of theater air showed. He states: "It appears from these examinations
that the air even in a tide-locked sewer does not differ from the
standard as much as many no doubt suppose."
A comparison of the number of bacteria found in a cubic foot of air
inside of a theater and in the street air would form a more convincing
statement, but I have been unable to find published records of any
such bacteriological tests. Nevertheless, we know that while the
atmosphere contains some bacteria, the indoor air of crowded assembly
halls, laden with floating dust, is particularly rich in living
micro-organisms. This has been proved by Tyndall, Miquel, Frankland,
and other scientists; and in this connection should be mentioned one
point of much importance, ascertained quite recently, namely, that the
air of sewers, contrary to expectation, is remarkably free from germs.
An analysis of the air in the sewers under the Houses of Parliament,
London, showed that the number of micro-organisms was much less than
that in the atmosphere outside of the building.
In recent years marked improvements in theater planning and equipment
have been effected, and corresponding steps in advance have been
made in matters relating to theater hygiene. It should therefore
be understood that my remarks are intended to apply to the average
theater, and in particular to the older buildings of this class. There
are in large cities a few well-ventilated and hygienically improved
theaters and opera houses, in which the requirements of sanitation
are observed. Later on, when speaking more in detail of theater
ventilation, instances of well-ventilated theaters will be mentioned.
Nevertheless, the need of urgent and radical measures for comfort and
health in the majority of theaters is obvious. Much is being done
in our enlightened age to improve the sanitary condition of school
buildings, jails and prisons, hospitals and dwelling houses. Why, I
ask, should not our theaters receive some consideration?
The efficient ventilation of a theater building is conceded to be an
unusually difficult problem. In order to ventilate a theater properly,
the causes of noxious odors arising from bad plumbing or defective
drainage should be removed; outside fumes or vapors must not be
permitted to enter the building either through doors or windows, or
through the fresh-air duct of the heating apparatus. The substitution
of electric lights in place of gas is a great help toward securing
pure air. This being accomplished, a standard of purity of the air
should be maintained by proper ventilation. This includes both the
removal of the vitiated air and the introduction of pure air from
outdoors and the consequent entire change of the air of a hall three
or four times per hour. The fresh air brought into the building must
be ample in volume; it should be free from contamination, dust and
germs (particularly pathogenic microbes), and with this in view must in
cities be first purified by filtering, spraying, or washing. It should
be warmed in cold weather by passing over hot-water or steam-pipe
stacks, and cooled in warm weather by means of ice or the brine of
mechanical refrigerating machines. The air should be of a proper degree
of humidity, and, what is most important of all, it should be admitted
into the various parts of the theater imperceptibly, so as not to cause
the sensation of draught; in other words, its velocity at the inlets
must be very slight. The fresh air should enter the audience hall at
numerous points so well and evenly distributed that the air will be
equally diffused throughout the entire horizontal cross-section of the
hall. The air indoors should have as nearly as possible the composition
of air outdoors, an increase of the CO_{2} from 0.3 to 0.6 being the
permissible limit. The vitiated air should be continuously removed by
mechanical means, taking care, however, not to remove a larger volume
of air than is introduced from outdoors.
Regarding the amount of fresh outdoor air to be supplied to keep the
inside atmosphere at anything like standard purity, authorities differ
somewhat. The theoretical amount, 3,000 cubic feet per person per hour
(50 cubic feet per minute), is made a requirement in the Boston theater
law. In Austria, the law calls for 1,050 cubic feet. The regulations
of the Prussian Minister of Public Works call for 700 cubic feet,
Professor von Pettenkofer suggests an air supply per person of from
1,410 to 1,675 cubic feet per hour (23 to 28 cubic feet per minute),
General Morin calls for 1,200 to 1,500 cubic feet, and Dr. Billings, an
American authority, requires 30 cubic feet per minute, or 1,800 cubic
feet per hour. In the Vienna Opera House, which is described as one of
the best-ventilated theaters in the world, the air supply is 15 cubic
feet per person per minute. The Madison Square Theater, in New York, is
stated to have an air supply of 25 cubic feet per person.
In a moderately large theater, seating twelve hundred persons, the
total hourly quantity of air to be supplied would, accordingly, amount
to from 1,440,000 to 2,160,000 cubic feet. It is not an easy matter to
arrange the fresh-air conduits of a size sufficient to furnish this
volume of air; it is obviously costly to warm such a large quantity of
air, and it is a still more difficult problem to introduce it without
creating objectionable currents of air; and, finally, inasmuch as this
air can not enter the auditorium unless a like amount of vitiated air
is removed, the problem includes providing artificial means for the
removal of large air volumes.
Where gas illumination is used, each gas flame requires an additional
air supply--from 140 to 280 cubic feet, according to General Morin.
A slight consideration of the volumes of air which must be moved
and removed in a theater to secure a complete change of air three
or four times an hour, demonstrates the impossibility of securing
satisfactory results by the so-called natural method of ventilation--i.
e., the removal of air by means of flues with currents due either to
the aspirating force of the wind or due to artificially increased
temperature in the flues. It becomes necessary to adopt mechanical
means of ventilation by using either exhaust fans or pressure blowers
or both, these being driven either by steam engines or by electric
motors. In the older theaters, which were lighted by gas, the heat of
the flames could be utilized to a certain extent in creating ascending
currents in outlet shafts, and this accomplished some air renewal. But
nowadays the central chandelier is almost entirely dispensed with;
glowing carbon lamps, fed by electric currents, replace the gas flames;
hence mechanical ventilation seems all the more indicated.
Two principal methods of theater ventilation may be arranged: in one
the fresh air enters at or near the floor and rises upward to the
ceiling, to be removed by suitable outlet flues; in this method the
incoming air follows the naturally existing air currents; in the other
method pure air enters at the top through perforated cornices or holes
in the ceiling, and gradually descends, to be removed by outlets
located at or near the floor line. The two systems are known as the
"upward" and the "downward" systems; each of them has been successfully
tried, each offers some advantages, and each has its advocates. In both
systems separate means for supplying fresh air to the boxes, balconies,
and galleries are required. Owing to the different opinions held by
architects and engineers, the two systems have often been made the
subject of inquiry by scientific and government commissions in France,
England, Germany, and the United States.