none at all. Many Andean towns have a combined water supply and sewer system consisting of an irrigation ditch flowing through the center of the street. At the upper end is supposedly potable water. At the lower, sewage, with the quality varying in between. Such better class residences as in most tropical towns have plumbing, use cess-pools or disposal into nearby open drains. Cess-pools and wells are often found in proximity and of similar simple construction. Where water supplies are pumped the source, if near the town, is liable to be polluted by ground water. Separate sewers to which rain waters are not admitted have been introduced by foreign enterprise only and very recently, in a few places where outside interests are active.

Sanitary conditions have little interest to the native inhabitants. Even those of the better class have ideas of childish simplicity as to what such conditions are. The ever-present "Zopilote" or buzzard takes care of the worst offenses, insects dispose of minor details and microbes are too small to be noticed. Many times objections have been encountered to new sewer designs on account of the use of small diameter house connections which were inadequate for the disposal of garbage.

The field for designs and construction of sewers in these countries is a large one, but its development will never proceed spontaneously for the subject meets little interest. The most useful aid to their construction is as incidents necessary before paving, which all can see and appreciate.

It is not implied that there are no Spanish-American engineers informed on matter of municipal engineering. That is far from the case, but in the tropical countries the number is very limited and these men, even though intelligent and well educated, must per force be of limited practical experience. The greatest fault to be found with some very able engineers met in Peru (where such training is much better than in any Central American country) was with the tendency to theorize on the basis of North American text books, forgetting the specialized field for which these were written. Again. a reputation as an authority, once established, persists long after its period of practical usefulness. The theories of Colonel Waring, for example, on sanitary sewers are still the last word on such matters to many engineers south of the equator, especially the idea that no sewer system can work without an elaborate installation of flush tanks.

It is believed that in all cases it is best to design separate systems of sewers for rainwater and sewage. Frequently the latter are all that is necessary both in regions where there is no rain and where it is excessive. In the latter case storm sewers may be required by local conditions, but often open drains and gutters will serve their purpose at less expense. This will, however, be the case only where the storm water has to flow but a short distance to reach an outfall.

There are many Central American cities where the run-off from the infrequent and short but intense rainfall is so great in volume as to require an elaborate system of storm sewers and inlets if street surfaces are to be protected and the streets made available for traffic at those times.

Sewer designs must be governed by the same rule as was noted for water supply; simplicity and security from the ignorance of local operating authority. For the sanitary sewers it must be kept in mind that they are for the use of communities that have never known them. House connections must be of small size to discourage their use for general garbage and waste disposal, grade should be adequate for self-cleansing velocities with low flow. Manholes must

be of simple construction with covers too heavy to permit of their use as public dumps. Flush tanks should be avoided as they will. inevitably cease to function from lack of maintenance. Necessary flushing can be done from time to time with a fire hose.

A means of discharge should be sought into some large body of water or stream at a point away from the community, where local pollution can do no harm. Conditions are seldom if ever such as to require purification plants. They are undesirable for two reasons: first, their cost; and second, their inability to function automatically. The time will come with the growth of population and the arrival of orderly government when systems for sewage treatment other than by dilution will be as necessary in the American Tropics as it is today in North America and Europe. Meanwhile any engineer working in any part of these regions except colonies under our own or foreign control, will do well, if he desires to obtain results of local benefit rather than material for lengthy reports, to stick to bare essentials.

STREETS AND HIGHWAYS:

In the countries of which we are treating the vital need today is for good means of communication. They are regions of the relatively vast areas that prevail in our country, with a density of population many times less, and with limited exceptions having no better means. of transport than that of the prehistoric races that formerly inhabited them. Poorer in many cases, for the highways and bridges of the Incas have disappeared from Ecuador and Peru and the ordinary Central American vehicle presents no improvement over those of the transport column that the Israelites took out of Egypt.

What these countries need is mileage of fair road designed with attention to grades and drainage, matters about which they are. utterly ignorant. What their towns require are not pavements rivalling New York or Paris (as their local authorities demand and never have) but street surfaces of moderate cost and simple maintenance.

The usual Central American road is only the trail made by the two-wheel ox-carts guttered by the rains until it becomes impassable and then abandoned for a similar trail alongside. Along the arid west coast of South America roads are practically non-existent. Roads passable for motor traffic are very infrequent. In Nicaragua there is no motor traffic outside the towns except after prolonged dry weather. Although there are hundreds of motor vehicles in Lima their use is confined within a ten-mile radius. Considerable money has been spent at times in various of these countries on roads but until recently it has been wasted without permanent result.

In the towns conditions in general are little better. Some few have macadam or stone block paving on the streets of major importance. A considerable extent of cobble or rubble surfacing can also be found, but the general practice is dirt surfaces with footways on either side built to suit individual taste without uniformity of level or width. Where streets are on grades liable to erosion, paved inclined ramps are built at intervals to prevent washouts. They, however, also serve to prevent traffic during heavy rains by distributing the run-off water to a uniform depth across the entire street due to their dam-like construction.

A realization of the needs of roads and streets is gradually appearing throughout the countries of the American Tropics. Salvador has paved the streets of its capital with asphalt and has entered on a comprehensive plan for a national system of highways. The paving and sanitation of the capital of Nicaragua is under way and other countries have similar plans. Some paving has been done in the capital of Peru though that country has yet to realize that mileage of fair roads is of more value than a few miles of costly first-class highway.

In fact the whole problem resolves itself into bringing to the authorities a realization that their needs are for an extensive skeleton of ordinary road laid out to permit of progressive future development and improvement, and in their cities similarly an economically possibly fairly good wearing surface on streets planned to be of suitable width and grades, well drained and provided with sewers and water connections. With such a basis heavier and more costly wearing surfaces can be provided when increasing traffic demands them.

Although I was responsible for the first concrete paving and the first block paving on concrete foundation ever laid in the American Tropics (in Panama City and the Canal Zone, twenty years ago) I believe that in few cases is such heavy construction justified. The ordinary tropical town will be adequately served with bituminous macadam street surfacing between concrete curbs and gutters. A fair grade of plain macadam or even gravel surfacing is all that can be justified on most country roads.

The improvement of street conditions in towns and cities is an obvious requirement and that is being undertaken with increasing frequency. Country highways have in few regions even been thought of. Outside of Santo Domingo under the American occupation and in Salvador today where national highway systems have been started there is little range for the use of the automobile.

In much of the territory fronting on the Caribbean Sea there is no means of transportation today available toward the interior except the rivers and the air.

Both in Central and South America there exists an untouched field for governments with sufficient interest in their countries' welfare to plan the nucleus of a highway system and for constructors with the knowledge and enlightened interest to recommend and carry out what is really needed.

THE SUGGESTED ORGANIZATION OF ENGINEERING DEPARTMENTS IN SMALL CITIES

By Harry Tucker, Professor of Highway Engineering, State College, Raleigh, North Carolina.

The writer has been prompted to prepare a paper on engineering departments in the smaller cities through his own observations and a careful study of the series of articles on "Engineering in the Small Cities" which have appeared from time to time in the Engineering News Record. A general summary of the results of the survey made by the Engineering News-Record, together with suggestions as to improving the engineering departments in such cities, was published in its issue of January 14th, 1926. It would be well for all those who are interested in the progress and welfare of our smaller cities to heed the suggestions given in the summary. And in presenting this paper, it is not the intention to give new suggestions for improvement, but rather to reiterate before a body of men so vitally concerned with municipal progress, the need for improvement in the engineering organization in these cities, and to emphasize suggested changes which, it is believed, will bring about the needed improvement.

Urban populations are rapidly increasing; therefore, our cities will continue to grow and extend physically. With this growth there must be continued improvement and extension of public service facilities, such as water, sewer and streets. Unless these services are under trained men-engineers-such growth will not be well planned and orderly. In the larger cities the engineering departments are generally well organized; in the smaller cities reverse is generally true. It is, hence, proper that we should consider the organization of the engineering departments in these cities, and to determine wherein improvement can be made.

Granting that the surveys made by the Engineering News-Record are representative of the conditions in the smaller cities, we would find 10 per cent of such cities without city engineers or city engineering organizations, 25 per cent with city engineers and excellent engineering organizations; while in the remaining 65 per cent of the cities there are engineering departments that are not adequate for carrying on the engineering work in these cities. The reasons for the absence of, or inadequate engineering departments in these cities may be traced largely to indifference on the part of the public, but other reasons would be: (1) the engineers themselves; (2) political interference; (3) false ideas of economy. It is believed that the public is rapidly awakening to the need for engineering services