Chapter 8

Another cause of the greater frequency of fires in New York and their more destructive nature is the greater density of population in that city. The London Metropolitan Police District covers 690 square miles, extending 12 to 15 miles in every direction from Charing Cross, and contained in 1881 a population of 4,764,312; but what is generally known as London covers 122 square miles, containing, in 1881, 528,794 houses, and a population of 3,814,574, averaging 7.21 persons per house, 49 per acre, and 31,267 per square mile. Now let us look at New York. South of Fortieth Street between the Hudson and East Rivers, New York has an area of 3,905 acres, a fraction over six square miles, exclusive of piers, and contained, according to the census of 1880, a population of 813,076. This gives 208 persons per acre. The census of 1880 reports the total number of dwellings in New York at 73,684; total population, 1,206,299; average per dwelling, 16.37. Selecting for comparison an area about equal from the fifteen most densely populated districts or parishes of London, of an aggregate area of 3,896 acres, and with a total population of 746,305, we obtain 191.5 persons per acre. Thus briefly New York averaged 208 persons per acre, and 16.37 per dwelling; London, for the same area, 191.5 persons per acre, and 7.21 per house. But this comparison is scarcely fair, as in London only the most populous and poorest districts are included, corresponding to the entirely tenement districts of New York, while in the latter city it includes the richest and most fashionable sections, as well as the poorest. If tenement districts were taken alone, the population would be found much more dense, and New York proportionately much more densely populated. Taking four of the most thickly populated of the London districts (East London, Strand, Old Street, St. Luke's, St. Giles-in-the-Fields, and St. George, Bloomsbury), we find on a total area of 792 acres a population of 197,285, or an average of 249 persons per acre. In four of the most densely populated wards of New York (10th, 11th, 13th, and 17th), we have on an area of 735 acres a population of 258,966, or 352 persons per acre. This is 40 per cent. higher than in London, the districts being about the same size, each containing about 1-1/5 square miles. Apart from the greater crowding which takes place in New York, and the different style of buildings, another very fertile cause of the spreading of fires is the freer use of wood in their construction. It is asserted that in New York there is more than double the quantity of wood used in buildings per acre than in London. From a house census undertaken in 1882 by the New York Fire Department, moreover, it appears that there were 106,885 buildings including sheds, of which 28,798 houses were built of wood or other inflammable materials, besides 3,803 wooden sheds, giving a total of 32,601 wooden buildings.

We are not aware that there are any wooden houses left in London. There are other minor causes which act as checks upon the spreading of fires in London. London houses are mostly small in size, and fires are thus confined to a limited space between brick walls. Their walls are generally low and well braced, which enable the firemen to approach them without danger. About 60 per cent. of London houses are less than 22 feet high from the pavement to the eaves; more than half of the remainder are less than 40 feet high, very few being over 50 feet high. This, of course, excludes the newer buildings in the City. St. James's Palace does not exceed 40 feet, the Bank of England not over 30 feet in height; but these are exceptional structures. Fireproof roofings and projecting party walls also retard the spreading of conflagrations. The houses being comparatively low and small, the firemen are enabled to throw water easily over them, and to reach their roofs with short ladders. There is in London an almost universal absence of wooden additions and outbuildings, and the New York ash barrel or box kept in the house is also unknown. The local authorities in London keep a strict watch over the manufacture or storage of combustible materials in populous parts of the city. Although overhead telegraph wires are multiplying to an alarming extent in London, their number is nothing to be compared to their bewildering multitude in New York, where their presence is not only a hinderance to the operations of the firemen, but a positive danger to their lives. Finally--and this has already been partly dealt with in speaking of the comparative density of population of the two cities--a look at the map of London will show us how the River Thames and the numerous parks, squares, private grounds, wide streets, as well as the railways running into London, all act as effectual barriers to the extension of fires.

The recent great conflagrations in the city vividly illustrate to Londoners what fire could do if their metropolis were built on the New York plan. The City, however, as we have remarked, is an exceptional part of London, and, taking the British metropolis as it is, with its hundreds of square miles of suburbs, and contrasting its condition with that of New York, we are led to adopt the opinion that London, with its excellent fire brigade, is safe from a destructive conflagration. It was stated above, and it is repeated here, that the fire brigade of New York is unsurpassed for promptness, skill, and heroic intrepidity, but their task, by contrast, is a heavy one in a city like New York, with its numerous wooden buildings, wooden or asphalt roofs, buildings from four to ten stories high, with long unbraced walls, weakened by many large windows, containing more than ten times the timber an average London house does, and that very inflammable, owing to the dry and hot American climate. But this is not all. In New York we find the five and six story tenement houses with two or three families on each floor, each with their private ash barrel or box kept handy in their rooms, all striving to keep warm during the severe winters of North America. We also find narrow streets and high buildings, with nothing to arrest the extension of a fire except a few small parks, not even projecting or effectual fire-walls between the several buildings. And to all this must be added the perfect freedom with which the city authorities of New York allow in its most populous portions large stables, timber yards, carpenters' shops, and the manufacture and storage of inflammable materials. Personal liberty could not be carried to a more dangerous extent. We ought to be thankful that in such matters individual freedom is somewhat hampered in our old-fashioned and quieter-going country.--_London Morning Post_.

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THE LATEST KNOWLEDGE ABOUT GAPES.

The gape worm may be termed the _bete noir_ of the poultry-keeper--his greatest enemy--whether he be farmer or fancier. It is true there are some who declare that it is unknown in their poultry-yards--that they have never been troubled with it at all. These are apt to lay it down, as I saw a correspondent did in a recent number of the _Country Gentleman_, that the cause is want of cleanliness or neglect in some way. But I can vouch that that is not so. I have been in yards where everything was first-rate, where the cleanliness was almost painfully complete, where no fault in the way of neglect could be found, and yet the gapes were there; and on the other hand, I have known places where every condition seemed favorable to the development of such a disease, and there it was absent--this not in isolated cases, but in many. No, we must look elsewhere for the cause.

Observations lead me to the belief that gapes are more than usually troublesome during a wet spring or summer following a mild winter. This would tend to show that the egg from which the worm (that is in itself the disease) emerges is communicated from the ground, from the food eaten, or the water drunk, in the first instance, but it is more than possible that the insects themselves may pass from one fowl to another. All this we can accept as a settled fact, and also any description of the way in which the parasitic worms attach themselves to the throats of the birds, and cause the peculiar gaping of the mouth which gives the name to the disease.

Many remedies have been suggested, and my object now is to communicate some of the later ones--thus to give a variety of methods, so that in case of the failure of one, another will be at hand ready to be tried. It is a mistake always to pin the faith to one remedy, for the varying conditions found in fowls compel a different treatment. The old plan of dislodging the worms with a feather is well known, and need not be described again. But I may mention that in this country some have found the use of an ointment, first suggested by Mr. Lewis Wright, I believe, most valuable. This is made of mercurial ointment, two parts; pure lard, two parts; flour of sulphur, one part; crude petroleum, one part--and when mixed together is applied to the heads of the chicks as soon as they are dry after hatching. Many have testified that they have never found this to fail as a preventive, and if the success is to be attributed to the ointment, it would seem as if the insects are driven off by its presence, for the application to the heads merely would not kill the eggs.

Some time ago Lord Walsingham offered, through the Entomological Society of London, a prize for the best life history of the gapes disease, and this has been won by the eminent French scientist M. Pierre Mégnin, whose essay has been published by the noble donor. His offer was in the interest of pheasant breeders, but the benefit is not confined to that variety of game alone, for it is equally applicable to all gallinaceous birds troubled with this disease. The pamphlet in question is a very valuable work, and gives very clearly the methods by which the parasite develops. But for our purpose it will be sufficient to narrate what M. Mégnin recommends for the cure of it. These are various, as will be seen, and comprise the experience of other inquirers as well as himself.

He states that Montague obtained great success by a combination of the following methods: Removal from infested runs; a thorough change of food, hemp seed and green vegetables figuring largely in the diet; and for drinking, instead of plain water, an infusion of rue and garlic. And Mégnin himself mentions an instance of the value of garlic. In the years 1877 and 1878, the pheasant preserves of Fontainebleau were ravaged by gapes. The disease was there arrested and totally cured, when a mixture, consisting of yolks of eggs, boiled bullock's heart, stale bread crumbs, and leaves of nettle, well mixed and pounded together with garlic, was given, in the proportion of one clove to ten young pheasants. The birds were found to be very fond of this mixture, but great care was taken to see that the drinking vessels were properly cleaned out and refilled with clean, pure water twice a day. This treatment has met with the same success in other places, and if any of your readers are troubled with gapes and will try it, I shall be pleased to see the results narrated in the columns of the _Country Gentleman_. Garlic in this case is undoubtedly the active ingredient, and as it is volatile, when taken into the stomach the breath is charged with it, and in this way (for garlic is a powerful vermifuge) the worms are destroyed.

Another remedy recommended by M. Mégnin was the strong smelling vermifuge assafoetida, known sometimes by the suggestive name of "devil's dung." It has one of the most disgusting oders possible, and is not very pleasant to be near. The assafoetida was mixed with an equal part of powdered yellow gentian, and this was given to the extent of about 8 grains a day in the food. As an assistance to the treatment, with the object of killing any embryos in the drinking water, fifteen grains of salicylate of soda was mixed with a pint and three-quarters of water. So successful was this, that on M. De Rothschild's preserves at Rambouillet, where a few days before gapes were so virulent that 1,200 pheasants were found dead every morning, it succeeded in stopping the epidemic in a few days. But to complete the matter, M. Mégnin adds that it is always advisable to disinfect the soil of preserves. For this purpose, the best means of destroying any eggs or embryos it may contain is to water the ground with a solution of sulphuric acid, in the proportion of a pennyweight to three pints of water, and also birds that die of the disease should be deeply buried in lime.

Fumigation with carbolic acid is an undoubted cure, but then it is a dangerous one, and unless very great care is taken in killing the worms, the bird is killed also. Thus many find this a risky method, and prefer some other. Lime is found to be a valuable remedy. In some districts of England, where lime-kilns abound, it is a common thing to take children troubled with whooping-cough there. Standing in the smoke arising from the kilns, they are compelled to breathe it. This dislodges the phlegm in the throat, and they are enabled to get rid of it. Except near lime-kilns, this cannot be done to chickens, but fine slaked lime can be used, either alone or mixed with powdered sulphur, two parts of the former to one of the latter. The air is charged with this fine powder, and the birds, breathing it, cough, and thus get rid of the worms, which are stupefied by the lime, and do not retain so firm a hold on the throat. An apparatus has recently been introduced to spread this lime powder. It is in the form of an air-fan, with a pointed nozzle, which is put just within the coop at night, when the birds are all within. The powder is already in a compartment made for it, and by the turning of a handle, it is driven through the nozzle, and the air within the coop charged with it. There is no waste of powder, nor any fear that it will not be properly distributed. Experienced pheasant and poultry breeders state that by the use of this once a week, gapes are effectually prevented. In this case, also, I shall be glad to learn the result if tried.

STEPHEN BEALE.

H----, Eng., Aug. 1.

--_Country Gentleman_.

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WOLPERT'S METHOD OF ESTIMATING THE AMOUNT OF CARBONIC ACID IN THE AIR.

There is a large number of processes and apparatus for estimating the amount of carbonic acid in the air. Some of them, such as those of Regnault, Reiset, the Montsouris observers (Fig. 1), and Brand, are accurate analytical instruments, and consequently quite delicate, and not easily manipulated by hygienists of middling experience. Others are less complicated, and also less exact, but still require quite a troublesome manipulation--such, for example, as the process of Pettenkofer, as modified by Fodor, that of Hesse, etc.

Hygienists have for some years striven to obtain some very simple apparatus (rather as an indicator than an analytical instrument) that should permit it to be quickly ascertained whether the degree of impurity of a place was incompatible with health, and in what proportion it was so. It is from such efforts that have resulted the processes of Messrs. Smith. Lunge, Bertin-Sans, and the apparatus of Prof. Wolpert (Fig. 7).

It is of the highest interest to ascertain the proportion of carbonic acid in the air, and especially in that of inhabited places, since up to the present this is the best means of finding out how much the air that we are breathing is polluted, and whether there is sufficient ventilation or not. Experiment has, in fact, demonstrated that carbonic acid increases in the air of inhabited rooms in the same way as do those organic matters which are difficult of direct estimation. Although a few ten-thousandths more of carbonic acid in our air cannot of themselves endanger us, yet they have on another hand a baneful significance, and, indeed, the majority of hygienists will not tolerate more than six ten-millionths of this element in the air of dwellings, and some of them not more than five ten-millionths.

Carbonic acid readily betrays its presence through solutions of the alkaline earths such as baryta and chalk, in which its passage produces an insoluble carbonate, and consequently makes the liquid turbid. If, then, one has prepared a solution of baryta or lime, of which a certain volume is made turbid by the passage of a likewise known volume of CO_{2}, it will be easy to ascertain how much CO_{2} a certain air contains, from the volume of the latter that it will be necessary to pass through the basic solution in order to obtain the amount of turbidity that has been taken as a standard. The problem consists in determining the minimum of air required to make the known solution turbid. Hence the name "minimetric estimation," that has been given to this process. Prof. Lescoeur has had the goodness to construct for me a Smith's minimetric apparatus (Fig. 2) with the ingenious improvements that have been made in it by Mr. Fischli, assistant to Prof. Weil, of Zurich. I have employed it frequently, and I use it every year in my lectures. I find it very practical, provided one has got accustomed to using it. It is, at all events, of much simpler manipulation than that of Bertin-Sans, although the accuracy of the latter may be greater (Figs. 3, 4, 5, and 6). But it certainly has more than one defect, and some of the faults that have been found with it are quite serious. The worst of these consists in the difficulty of catching the exact moment at which the turbidity of the basic liquid is at the proper point for arresting the operation. In addition to this capital defect, it is regrettable that it is necessary to shake the flask that contains the solution after every insufflation of air, and also that the play of the valves soon becomes imperfect. Finally, Mr. Wolpert rightly sees one serious drawback to the use of baryta in an apparatus that has to be employed in schools, among children, and that is that this substance is poisonous. This gentleman therefore replaces the solution of baryta by water saturated with lime, which costs almost nothing, and the preparation of which is exceedingly simple. Moreover, it is a harmless agent.

The apparatus consists of two parts. The first of these is a glass tube closed at one end, and 12 cm. in length by 12 mm. in diameter. Its bottom is of porcelain, and bears on its inner surface the date 1882 in black characters. Above, and at the level that corresponds to a volume of three cubic centimeters, there is a black line which serves as an invariable datum point. A rubber bulb of twenty-eight cubic centimeters capacity is fixed to a tube which reaches its bottom, and is flanged at the other extremity (Fig. 7).

The operation is as follows:

The saturated, but limpid, solution of lime is poured into the first tube up to the black mark, the tube of the air bulb is introduced into the lime water in such a way that its orifice shall be in perfect contact with the bottom of the other tube, and then, while the bulb is held between the fore and middle fingers of the upturned hand, one presses slowly with the thumb upon its bottom so as to expel all the air that it contains. This air enters the lime-water bubble by bubble. After this the tube is removed from the water, and the bulb is allowed to fill with air, and the same maneuver is again gone through with. This is repeated until the figures 1882, looked at from above, cease to be clearly visible, and disappear entirely after the contents of the tube have been vigorously shaken.

The measures are such that the turbidity supervenes at once if the air in the bulb contains twenty thousandths of CO_{2}. If it becomes necessary to inject the contents of the bulb into the water twice, it is clear that the proportion is only ten thousandths; and if it requires ten injections the air contains ten times less CO_{2} than that having twenty thousandths, or only two per cent. A table that accompanies the apparatus has been constructed upon this basis, and does away with the necessity of making calculations.

An air that contained ten thousandths of CO_{2}, or even five, would be almost as deleterious, in my opinion, as one of two per cent. It is of no account, then, to know the proportions intermediate to these round numbers. Yet it is possible, if the case requires it, to obtain an indication between two consecutive figures of the scale by means of another bulb whose capacity is only half that of the preceding. Thus, two injections of the large bulb, followed by one of the small, or two and a half injections, correspond to a richness of 8 thousandths of CO_{2}; and 5½ to 3.6 thousandths. This half-bulb serves likewise for another purpose. From the moment that the large bulb makes the lime-water turbid with an air containing two per cent. of CO_{2}, it is clear that the small one can cause the same turbidity only with air twice richer in CO_{2}, _i.e._, of four per cent.

This apparatus, although it makes no pretensions to extreme accuracy, is capable of giving valuable information. The table that accompanies it is arranged for a temperature of 17° and a pressure of 740 mm. But different meteorological conditions do not materially alter the results. Thus, with 10° less it would require thirty-one injections instead of thirty, and CO_{2} would be 0.64 per 1,000 instead of 0.66; and with 10° more, thirty injections instead of thirty one.

The apparatus is contained in a box that likewise holds a bottle of lime-water sufficient for a dozen analyses, the table of proportions of CO_{2}, and the apparatus for cleaning the tubes. The entire affair is small enough to be carried in the pocket.--_J. Arnould, in Science et Nature_.

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[NATURE.]

THE VOYAGE OF THE VETTOR PISANI.

Knowing how much _Nature_ is read by all the naturalists of the world, I send these few lines, which I hope will be of some interest.

The Italian R.N. corvette Vettor Pisani left Italy in April, 1882, for a voyage round the world with the ordinary commission of a man-of-war. The Minister of Marine, wishing to obtain scientific results, gave orders to form, when possible, a marine zoological collection, and to carry on surveying, deep-sea soundings, and abyssal thermometrical measurements. The officers of the ship received their different scientific charges, and Prof. Dohrn, director of the Zoological Station at Naples, gave to the writer necessary instructions for collecting and preserving sea animals.

At the end of 1882 the Vettor Pisani visited the Straits of Magellan, the Patagonian Channels, and Chonos and Chiloe islands; we surveyed the Darwin Channel, and following Dr. Cuningham's work (who visited these places on board H.M.S. Nassau), we made a numerous collection of sea animals by dredging and fishing along the coasts.

While fishing for a big shark in the Gulf of Panama during the stay of our ship in Taboga Island, one day in February, with a dead clam, we saw several great sharks some miles from our anchorage. In a short time several boats with natives went to sea, accompanied by two of the Vettor Pisani's boats.