G. R. G. Conway

“ Cabral, during the crisis, daily illustrates the necessity. He wages war upon incompetent medical men, portrays the risk the pedestrian takes on the crowded streets of the Capital, the evil effects of unlawful strikes, and so on;—every phase in the everchanging life of the Capital is eloquently depicted. In some of his cartoons of persons he subordinates caricature in favor of true portraiture, and in others, the kindly sympathetic personality of the artist changes rapidly into the satirist and cynical student of life with an ineradicable memory of its shams and miseries. ”

“ Cabral’s amazing drawings are worthy of taking rank with those of the most distinguished foreign cartoonists. He can, with equal facility, produce the most humorous of cartoons or the most satirical of caricatures. In his cartoons of representative people, he seems to extract by critical penetration—sympathetically—the quintessential expression of his subject. He is always an artist, a consummate designer and a psychological observer who analytically peers into the minds of men and lays bare their personalities. His art is versatile. In line, he excels as no other Mexican artist ”

“ It is desirable, of course, to get as much capacity in works as one can for the outlay, but there are instances where one can get too much for the money, as where a larger pipe than is necessary is used for a sewer, merely because it costs about the same as a smaller one, and as a result the cost of maintenance is permanently increased. ”

“ If all the sewers of a system are too large, the condition is incurably bad; while, if a few miles prove to be too small, on account of growth and prosperity not anticipated by the designer, it will be easy enough to relay such parts when this becomes necessary.
Mr. Conway states that:
"The sewers are designed on a very liberal basis, namely, on the assumption that when flowing half full the quantity to be dealt with will be 380 liters [100 gal.] per capita per day, with a maximum rate of flow of 200 per cent." ”

“ He was a magic worker, using his remarkable art to impress his less skilled brother. The caricaturist belongs to a much later period; but he, too, was in evidence in Greece during the days of Aristophanes, a century or two before the artistic genius of the Maya race carved and modelled their quaint, grotesque figures of men and animals. That the art of caricature is an ancient one in Mexico we have abundant evidence. The artist usually worked in clay, but he also made drawings with pointed obsidian knives or charcoal on stone. ”

“ Moreover, crops not intended for human consumption, which are grown on lands irrigated by sewage bearing typhoid germs, etc., are unsafe for men to handle; even to store them may cause a dissemination of disease. It is evident, therefore, that the whole sewage flow should be in some manner disinfected at least, if not filtered, before it is used.
The method of sewage disposal and the use of merely settled septic sewage for irrigation seem to be open to objection. ”

“ The practice of calculating sanitary sewers to run half-full is a good one when ground-water is expected in sufficient amount to fill the remaining portion of the sewer, but when no ground-water, or roof-, or surface-water is allowed to enter the system, or all precautions are taken to exclude such, then the system may be designed so that the expected maximum, or wash-day flow, will fill the sewer to the desired hydraulic gradient. ”

“ A great political question, such as the official American recognition of President Obregon’s Government, finds Cabral sympathetically interpreting the international aspirations of the Mexican people. The danger of Bolshevism in the State of Veracruz becomes a subject for many convincing cartoons, of more influence than dozens of leading articles. Mexico City, due to an exceptional drought, is called upon to economize in its use of electric energy and daylight-saving is officially established for a time. ”

“ It would probably be difficult to find in the United States a city of 85,000 inhabitants, previously totally lacking either a water supply or sewerage system, which, under a consistent and harmonious design, has been provided with both in the degree of completeness and structural excellence exemplified in the works at Monterrey. ”

“ Designing the sewers to flow half full for all diameters less than 18 in., and seven-tenths full for all larger sizes, it would seem that this would give ample capacity for all time to come in such a city, and that good practice would not exceed these figures, it being more desirable that the sewers should not be too large to work well, than that they should be large enough in all places to meet every possible contingency. ”

“ But the art of satirical expression can only be developed when some degree of freedom obtains. Under Spanish rule and the rigid jurisdiction of the Inquisition no freedom of thought was possible. With the changed conditions brought about by the separation of New Spain from the mother country there was liberty enough—and even license—for the caricaturist, which he used with biting satire against the ever-changing political heroes. ”

“ The best sizes for the sewers in a given system is always a matter to be determined by local conditions; but there seems to be no reason why the 6-in. size should not be used where the flow is so slight that the 8-in. will not work well; or where the velocity must of necessity be so great that a flotation depth of flow cannot be maintained in the larger size. As to likelihood of clogging and stoppage, the writer's opinion, based on the maintenance of three rather extensive systems in different parts of the United States, in each of which the 6-in. ”

“ A stream having a depth of flow sufficient to immerse solid matter held in suspension, to a certain extent lifts it and carries it forward. The entire surface is also exposed to the action of the current. A stream having an equal velocity but a less depth in proportion to the diameter of the solid matters to be transported, evidently has less transporting power. * * * An amount of sewage which can be properly transported by a circular sewer of a given size, cannot be as efficiently transported by one of larger diameter. ”

“ In the writer's opinion, the waters of this and similar rivers in the State pass through many open caverns underground, so that experience gained in the investigation of underflow waters in other places would be insufficient to determine the quantity passing at any point along the river if ascertained by merely computing it from the velocity of the underflow and the area of the water-bearing gravels. The rainfall on the water-shed of the Santa Catarina River is probably 25% greater than at Monterrey, and all ordinary rains sink rapidly into the limestone soils and quickly disappear. ”

“ The high death rate is caused by the excessive infantile mortality, which is so prevalent throughout the whole of Mexico. The climatic condition of Monterrey, with its exceptionally healthy subsoil, ought to make it one of the healthiest of cities, if proper care were taken to enforce sanitary laws. The data regarding typhoid mortality are probably 480 understated, as they were compiled by the writer, in the absence of any official publications, from the actual death certificates, but no special care is taken by the authorities to insure accuracy in such certificates. ”

“ In designing a sewer system in older and well-established communities, the engineer is generally able to compile considerable information regarding the probable sewage flow for which it is necessary to provide. In Monterrey this quantity was absolutely unknown. The writer's practice in other places has been to assume that about 8% of the total daily discharge of sewage will flow off in one hour; and, from many curves which he has plotted regarding sewage flow in British towns, this rate appears to him to be approximately correct. ”

“ The much-maligned sewage-farm still may be allowed (where the conditions are favourable) to rank as one of the best methods of sewage-disposal. Diverse opinions may be held as to what are favourable conditions, particularly as conditions are sure to vary widely with locality; but it may be assumed that where there is 1 acre of suitable land per 100 persons, as in Berlin and several other important cities, the efficiently-worked sewage-farm, when judged solely by the standard of the effluent produced, is still in the front rank. ”

“ The grade should be such, and the collecting system so laid out, that the flow may be conserved as far as possible, and the sewage flow should be kept of as great a depth in the invert, or bottom of the sewer, as safety in self-cleansing velocity will permit. This will save flush-water and prevent stoppages, and thus reduce the cost of maintenance to a minimum. For good sanitary practice, the sewers should be designed, first of all, to comply with the requirements of the present, or immediately expected, ordinary flow, with some reasonable allowance for the future. ”

“ It has also become the frequent practice of designers to give every length of sewer all the grade possible, regardless of the fact, taught both by hydraulics and experience, that the best grade is that which will give as much depth of flow as is consistent with a scouring velocity. ”

“ No works, with a long preliminary history, such as those at Monterrey, can rightly be said to be due to any one individual; many engineers contributed to the final result, and the writer willingly acknowledges his indebtedness to the able men, who, for ten years prior to the construction of the 581works, investigated the particular problems which were met—problems which were not only of an engineering and physical nature, but racial and financial. ”

“ Monterrey lies in a plain at the foot of the Eastern Sierra Madre Mountains which constitute the eastern margin of the Mexican Cordilleran 477Plateau, and is surrounded by the magnificent mountains of that group, among the most notable of which are the beautiful Mitra and Silla Mountains. In the neighborhood of Monterrey these mountains attain heights of from 2,000 to 2,400 m., and are noted for their broken and jagged sky-lines. The leading geological characteristics of the district are the uplifted limestones of the older cretaceous age which form the main mass of the mountains. ”

“ To do this a by-pass was taken from the sewer a short distance before reaching the site of the tanks. By properly timing the flow, arrangements could be made to discharge these waters in the early hours of the morning, by allowing the scour-pipes in the distribution system to be opened at night when the domestic sewage flow was at its minimum. As the area of land available is very great, the degree of purification in the tanks was relatively unimportant; the object to be obtained consisted chiefly in distributing on the land an effluent which would be innocuous and clear. ”

“ Practically, the water-bearing strata are not limited merely to the sand and coarse gravels, as the clay formation lying above and below them is full of small gravel deposits containing considerable volumes of water. The main direction of the underflow is toward the east, and the hydraulic gradient, which was established from wells sunk farther west, was found to be approximately 1%, or practically the same as the average surface of the bed of the river above the line of the infiltration gallery. ”