A P . , =9=7
T H E J O U R N A L OF INDL‘STRIAL A N D ENGINEERING C H E M I S T R Y
How then can the detonation of an explosive be carried over a n intervening air space? The thermal hypothesis will not account for this. This is explained by the compression and rarefaction of the surrounding air. Since the force of such waves decreases as the square of the distance, this theory is not sufficient. From what has been said, it can be seen to be a very complex subject, and how many theories fail u-hen all the facts are taken into consideration. DETONATORS
For many years mercury fulminate has held its place as a detonating substance as superior to all others. Of recent years, however, its place has been threatened by other compounds which bid fair to displace it. One of the most promising of these is lead azide; lead azide is a salt of hydronitric acid whose constitution is expressed thus:
1I
N> N
NH.
Some investigators
unite i t thus: hTEF S=N-H. This acid forms a great number of salts, as mercury azide, silver azide and sodium azide. The heavy azides, such as lead azides, are prepared by treating a solution of sodium azide with a soluble metallic salt, such as lead acetate, the sodium azide being prepared from nitrous oxide and sodium amide. Large ,crystals of lead azide and mercuric azide have been found to be very sensitive to mechanical shock, the sensitiveness increasing with the size of the crystals. Even the breaking of a single large crystal is said t o bring about explosion. Crystals as large as 3 mm. in length, when dry, often explode when brushed with a feather. If a hot saturated solution be allowed to cool slowly, large crystals sometimes form, which detonate under water. The formation of such crystals must be avoided. This property is scarcely obtainable with the fulminates. Mercury fulminate and lead azide differ very greatly in flash point-lead azide flashing about 330 ’, mercury fulminate flashing about 180’. Lead azide in fine crystals appears t o be less sensitive t o blow than mercury fulminate. It is very stable when stored at high temperatures, such as 50’ C.; it is, however, decomposed by strong sunlight. The action of lead azide upon metals is slight, while fulminate is quite active. Mercury fulminate may be dead-pressed, while lead azide increases it brisance and explosive power with pressure. If detonator caps be loaded with lead azide and a booster charge, much less lead azide is necessary to produce the desired detonation. The sensitiveness of fulminate to mechanical shocks is much lessened by the presence of as much as I per cent moisture, while lead azide is not much lessened by this small amount. This particular property is extremely valuable in case of storage of detonating caps in humid atmosphere. Many other substances have been proposed as detonating agents. Trinitro-resorcine or lead styphnate [CsH(N0z)sOzPb] has been found to be an excellent explosive. Hexamethylamine tri-peroxide-diamine [N(CH*O.OCH:),N] is said to exceed mercury fulminate 4 or 5 times in priming power. A number of others rnay be mentioned as: Nitrogen tetra-sulfide, iT&. Diazo-benzol-nitrate, CEH~NOZ-NO~. 0 NO = C( \Hg
Perchlorate of tri-mercur-aldehyde, C104Hg(Hg20 = C-COH). Dr. Alfred Stettbacher, in Zeitschrift f u r das geramte ScRiess zind Sprengstofzuesen, of Oct. I and Dec. I , 1914, has presented a most splendid resume of recent developments in this field, from which paper I have drawn freely. FRANKFORD ARSENAL PHILADELPHIA, Pa.
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WATER-METERS IN THEIR SANITARY RELATIONS‘ By HENRYLEFPMANN Received September 30, 1916
The management of an American city is the despair of the efficiency expert. Ex-President Taft expressed the view that in two respects the promise of better things that had been seen in the formation of the United States under the Constitution had seriously failed of fulfilment: procedures in courts and the administration of American cities. The administration of civil and criminal law in most parts of this country is legalized robbery, and the business and engineering administration of cities is chiefly remarkable for stupidity and dishonesty. I come from a city that has been widely advertised as “corrupt and contented,” and daily experience compels me to admit the substantial accuracy of the phrase. In spite of the development of the science of city-planning, miles of small streets are allowed to be laid out, and while the street prism is being excavated for water and gas supply and for telephone conduits, no provision is made for electric light and power wires. High-tension currents are permitted to be carried on hideous poles through residential districts, involving danger to persons and property, and subjecting the service to frequent interruptions from storms. Situated with an enormous supply of fresh water a t its boundaries, which, by the construction of simple storage reservoirs, could have been rendered safe for all uses, it was for many years one of the worst typhoid nests in the world. Now, after spending many millions for installing a plant for purification of these supplies, its “Solons” are debating the problem of meeting a greatly increased demand, and, instead of seeking rational means of preventing waste, are looking towards an expensive enlargement of the plant. I am presenting this paper, however, not to inveigh against any particular municipal administration, but to call attention to a relation between engineering and chemistry that I think is often overlooked. I have long felt that the main sanitary problems of municipal administration are essentially engineering ones, and that undue emphasis is given to the purely chemical data. There is, of course, no phase of municipal sanitation more important than water supply. Water, by the very necessities of our existence, is largely consumed now, and it must be furnished freely and continuously in a perfectly safe condition. We are, unfortunately, accustomed to regard it as without price; we think it should be “as free as air,” b u t this cannot be expected in municipal life, and the sooner the citizen realizes that water should be paid for like food, clothing and transportation, the better for all of us. Indeed, it would be well if the community could be brought to feel that water of high purity is a luxury and should command a good price. The interrelation between chemistry and engineering becomes still more intimate by the growth of the modem practices of sewage disposal. It has become necessary not only to secure an abundant supply of good water, but to restore it to reasonable purity after it has been used. The time is rapidly passing when a community rnay take as it pleases from the upper reaches of a stream, and throw into the lower reaches its drainage. From two points of view comes, therefore, the need for preventing water-waste, and thus the question of a controlled distribution is brought vividly to the notice of the sanitarian. Such control may be obtained in two ways: by an intermittent distribution, the places supplied being provided with storage tanks, thus limiting the amount of water available during the 24 hours, or by measuring the water delivered to each consumer and charging for it, with a minimum rate. The storage-tank method with intermittent pumping is used in many foreign cities, and has some features to recommend it, but with the lavish use of water among Americans, very large tanks would be 1 Presented at the 53rd Meeting of the American Chemical Society, ?Yew T o r k City September 25 t o 3 0 , 1916.
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needed. The meter-system is preferable. The mechanical problems in regard to water-meters are solved and many forms that are accurate, inexpensive and durable are available. I have residential experience in but two cities, Philadelphia and Atlantic City, but it happens that these present a decided contrast in the matter of water-supply, and serve well to illustrate the point that I wish to discuss. Philadelphia has been notoriously wasteful of water. This is not due to any tendency to excessive cleanliness. Although about the middle of the 19th century it was often praised by visitors for the conditions of its streets, yet it rapidly fell from grace in this respect, and except as to an incomprehensible and reprehensible practice of frequently washing the sidewalks, it shows, at present, a good deal of general neglect in street manI agement. Many years ago, an English visitor-”upper, think-said that “the carriage-ways are always dirty and the footways always clean.” At the present time, owing to lack of system for control of the distribution, the consumption is about 300 gals. per person per day; an enormous amount, surely indicative of great waste. Metering is almost non-existent. A few householders have discovered that by installing meters a considerable saving of water rent may be secured, but this is merely the ‘outcome of the ridiculously low meter rates. For some years, indeed, the city ordinances forbade the installation of a meter in a private house, and left it practically optional t o large establishments. The mass of consumers are on a flat rate, that is, based on what they may, not on what they do use. How any person charged with the administration of a municipality in any capacity can be so indifferent to business methods as to favor such a method would seem to be beyond human comprehension, but it is after all a “strictly business” matter. Large manufacturing establishments and certain private individuals are interested in maintaining conditions which permit them to use water unrestrictedly, while paying less than their proper share of the expense of the supply, and as these persons exert a good deal of support to the dominant political party, especially in the matter of campaign contributions, a subservient administration ignores the just method. Turning to Atlantic City-which offers an interesting contrast t o Philadelphia, in this as in some other respects-we find according t o the 1915 report of the Water Department, that nearly the entire consumption is metered, and that during the months in which the visitors are comparatively few (October to May) the consumption is about 150 gals. per person per day. It must, however, not be overlooked that many hotels have an independent supply from artesian wells, and that the city has almost no industries that are large water users. On the other hand, during the dull season, it is especially the large hotels that are running a t restricted output, and bathing is a special feature of the resort. This is largely sea-bathing, yet even this necessitates the use of fresh water both for rinsing the person and for the laundry of bathing suits. Most of the large renting establishments now have running fresh water in every room The fact that residents are required to pay for the water used does not seem to cause any undue restraint in the ordinary uses, though, of course, it tends t o the installation of good plumbing and to keeping this in repair. The consumption per person in Philadelphia is somewhat difficult to determine, and in any case, regard must be had to the fact that the city is spread over a wide area, and contains a very large number of industrial establishments that are heavy water users. Private sources of supply are not numerous. As a rule, both the subsoil and deep water obtainable within the city limits is unfit for drinking and manufacturing purposes. The pumping data show that frequently the consumption is about 300 gals. per person per day, a s noted above, but this figure is based on what is termed by engineers “plunger displacement” and is generally regarded as too high. Moreover,
YoI. 9 , NO. 4
it does not consider leakage in the street distribution system, which is probably rather high. House leakage, especially in the flushing apparatus, is very high. It is hardly necessary to present any statistics of water waste in American cities for nearly every one is aware of it, but as a brief illustration I give the results of an investigation made a few years ago by John C. Trautwine, Jr., who was for several years chief of the Bureau of Water of the City of Philadelphia. A block of the characteristic two-story, small-street dwellings was utilized. Number of dwellings (7-roomed). . . . . . . . . . . . . . . . . . 142 782 Total number of openings.. Number leaking slightly. 22 Number running continually.. 32 Gallons delivered in 24 hours.. . . . . . . . . . . . . . . . . . . . 119.800 103,600 Gallons wasted by leakage.. Gallons per capita: Delivered. . . . . . . . . . . . . . . . . . . . 222 Actually used.. 30 192 Wasted
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A large portion of the waste is brought about by a small proportion of users, so that a restriction by metering would affect mostly those who are indifferent to the welfare of others. As I ,remarked above, the problem of waste-prevention has assumed an additional interest by reason of the necessity of sewage purification. All communities, and even occupiers of isolated country houses, now recognize that the effluept water must be brought to a fair condition of organic purity, a t least, and that the greater the dilution of this effluent the greater the cost and difficulty of treatment I n the discussion of this subject, the main opposition to measured supply comes from the owners of manufacturing establishments and from a limited number of well-meaning, but misguided people, who believe that some harm will be done if any restriction should be put on the use of water. Their slogan is that “water should be free as air” and that everybody should be encouraged to be clean. A careful examination of the houses in which the worst leakages occur would probably show no greater degree of cleanliness than in those in which the plumbing is kept in repair and the water used with judgment. The truth is, however, that the same line of argument that is used to prevent the introduction of meters may be used to justify free distribution of food and beverages and free amusement. Moreover, all the data available show that all reasonable requirements may be met by the system of assigning a minimum allowance, and changing a flat rate, imposing additional charges only by those who exceed this. Careful investigations in American cities have shown that 7 cu. ft. (somewhat over 50 U. S. gallons) per person, per day, will meet all necessities in a high-class home in a large city. In Philadelphia, at present, a minimum charge of $8.00 per year allows the use of 200,000 gals., but this is much too large, and it is proposed to raise the price and reduce the allowance so that $ 1 2 . 0 0 will be charged for 90,000 gals. per year, which in a household of five persons will give about 7 cu. ft. per person per day. Briefly, then, my thesis is that in view of the importance of pure water the enormous amount now required, and the necessity of purification of sewage, the sanitary engineer and chemist should use every effort to have public water supplies managed with rigid prevention of wastes and reckless use, and that this cannot be done without complete metering of the supply. Consumers should be taught that principles of conservation of resources, as well as proper management of filtration and sewagedisposal plants, require such a system, and further that the installation of meters with the provision of a‘ minimum charge does not interfere with the use of water as freely as health and comfort require. Municipal supplies must depend almost entirely on surface waters. Here and there, artesian and subsoil sources may be available, but these exceptions are of no practical importance. I am still of the opinion that I expressed
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many years ago in a paper before the Pennsylvania State Board of Health, that unpurified surface-water is alwa.ys unfit for drinking, and that, as concerning it, analyses-bacteriological and chemical-are academic. The object of science is, of course, the discovery of truth, and from this point of view, any addition to knowledge, whether the discovery of a new marking on Mars or the properties of the circle in non-Euclidian space, must be appreciated, but the sanitarian deals with the purely utilitarian phase of science. I think there is no more important problem before the people of the United States than the conservation of the water supply, and i t is the duty of informed persons to insist with all possible energy upon the necessity in economy in the use of water, for maintaining the quality of the original material and for reducing the cost of the subsequent purification of the effluent. For these reasons, :[ regard the water-meter as a most important sanitary agent. 1839 N. 1 7 STREET ~ ~ PHILADELPHIA
ADVANTAGES OF SOFTENED WATER IN LAUNDRY WORK’ B y J. H. RYAN
Received r\-ovember 8, 1916
My topic to-day is what advantage softened water has over hard water, the saving not only t o the laundryman, but also t o the customer, and what the possibilities are for the equipment of a modern laundry with an efficient water-softening plant. The laundries of this country in 1914transacted business amounting to $142,503,350, and there was paid for labor $7 I ,764,059 ; the amount invested in machinery, equipments, These figures give some buildings, etc., was $98,055,000. idea of the magnitude of the laundry business, and yet, as a matter of fact, it is still in its infancy. The majority of the laundries in this country are devoting most of their time to the laundering of the provincial stiff collar and shirt, but this portion of the business is by far the smallest part of the work that the average American home has t o offer. For example, one man in Michigan decided he would enter the family wash field and in less than one year increased his business over $1400 per week. When the American laundry is properly equipped and makes the proper effort to obtain this class of work, the field is practically unlimited. It might be well for us t o consider for a moment the class of work, also the difficulties that the laundrymen have to contend with. Laundry is cosmopolitan in its service. There is, of course, a wide range in the quality of the fabrics treated. Not many years ago fabrics manufactured in this and other countries were heavier, very much stronger and would therefore stand more grief in the laundry. This class of goods is seldom ever used now; it has been replaced with thin delicate fabrics which are “loaded,” sometimes t o the extent of from I O to 70 per cent in order to make them heavy and apparently more durable Aside from this, every conceivable color known comes to us from day t o day, which, in treatment, must receive the utmost care. Hence, the problem is a very different one from that of twenty years ago. The question that the laundrymen are trying t o solve is how t o do this class of work for American homes with the least wear and tear and a t the lowest possible cost. For more than a quarter of a century I have been in the laundry business. About half of that time I was connected with a laundry that used hard water exclusively. I can hest illustrate the point I am trying: to make by giving you a little personal experience I had more than twenty years ago. I n those days we heard very little about water analysis, or a t least the laundrymen knew very little about it. All they knew about washing 1 Read a t the 52nd Meeting of the American Chemical Society, UrbanaChampaign, Illinois, April 18 t o 2 1 , 1916.
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was this: if they used plenty of caustic soda or soda ash in the soap and a plentiful supply of bleach, their clothes would come out of the machine clean, but very often they were in serious difficulties and did not know just why; neither did they know just how to work their way out of their troubles. The story I am about to tell you will demonstrate beyond any question of doubt, the value of water softening in a laundry and the danger of using hard water. The laundryman I worked for was troubled a great deal with a yellow or brown cast in his work. His collars always had yellow seams. He insisted that it was the iron in the water that was causing this trouble and a t a considerable expense he installed a filter, but this did not do away with his difficulty. rlt that time, and even now, a great many of the laundrymen use chloride of lime and soda for bleaching purposes; soda is used to soften the bleach, in other words to prevent it from destroying the soap. It mattered very little how much of this bleach was used, there would still be yellow seams and edges on the collars. About this time I read somewhere that oxalic acid was a good bleacher, so I made up my mind that I would do a little experimenting on my own account. I took some collars home and prepared a solution of oxalic and water; in this solution I placed the collars, rinsed them, and immediately the yellow seams vanished but a green tint remained and I had considerable difficulty in washing out the effects of the acid. After the proprietor had inspected the work, he asked me one day how I did it and I told him I had a new bleach; he thought so favorably of the work I was doing that he offered to form a stock company, if I would turn over the formula to them so they could manufacture it. About this time I became a little negligent about washing the green tint out of the collars, so one day when I had an extra large amount of collars delivered to my home and did the necessary work, the foreman and the proprietor made up their minds I was using sulfuric acid; they proceeded to experiment, sent out for a bottle of sulfuric acid, filled a wooden pail threequarters full of water and poured in the acid until they thought the solution was sufficiently strong t o do the work. They then rinsed in this solution a nightshirt which had a decided yellow tint; the third time the garment went into the pail the boss found himself hanging onto two sleeves, the rest of the nigh tshirt resting quietly and unattached in the pail; but i t had the green tint the same as I had left in the collars ; after this operation was over I told them of my secret bleach and when they used oxalic acid in their rinsing and blueing water in sufficient quantities the yellow edges would disappear. This particular laundryman never knew just why or how the acid was taking care of the yellow seams, neither did he know just what was making the yellow seams; it was the result of attempting to break hard water in the machine by using an excessive amount of alkali. It is not necessary for me to go into detail in attempting t o bring to your minds the great hazard the laundryman takes when he attempts to break hard water in the machine, especially when it is loaded with clothes. You might ask me if there is any danger in using soft ivater when the water is treated in a water softener. The facts are that the danger is identical with that of the hard water. so far as the use of acid is concerned; the minute the alkalinity is raised above 7 grains trouble starts and then the acid remedy will have to be applied. There are three water softener systems that are generally used in the laundries of this country: the intermittent, the continuous and the four-pipe systems. The intermittent system is seldom used, so it leaves the field open, practically speaking, to the continuous and four-pipe systems. About twelve years ago, we had what was known as the old Tweedale system of water softening. The process of treatment
