quiet; moderate and rainy; moderate, fair and windy; moderate, fair and quiet; cool and rainy; cool, fair and windy; cool, fair and quiet; cold and snowy; cold, fair and windy; cold, fair and quiet; cold, windy and snowy. Maps of the various types have been made. They show quantitatively what we have long known qualitatively from the usual standard maps of special phases of single elements. Percentages of weather types may be used in teaching. Instead of impressing on the pupil that some distant place has a certain mean summer temperature he may be told that this place has a climate made up of various percentages of weather types, many of which he has experienced at home. Thus he is learning about the weather as it occurs and not the climate as the agglomeration of single factors. Doctors sometimes have occasion to send patients to places with a certain kind of climate, but have no definite information as to where that place may be. An insurance company fortified by a map of type percentages is able to set rates better than a company which "takes a chance." It is hoped that these maps and tables of weather types supplementing others may give us a better idea of our climate and be of use along other lines. Weather types in the climate of Mexico, the Canal Zone and Cuba By J. ELMER SWITZER, Indiana University This study of the weather types in the climate of certain cities of Mexico, the Canal Zone, and Cuba is an effort to ascertain the actual weather experienced from day to day by the inhabitants of this section within the Tropics. The stations studied are Colon and Balboa Heights in the Canal Zone; Vera Cruz, Progreso, and Matamoros on the east coast, Salina Cruz and Manzanillo on the west coast, Mexico City on the plateau of Mexico, and Habana, Cuba. The type of weather for each day for the above stations for the five-year period, 1917-1921, were charted, their averages determined and charted. The types of weather used were, hot and rainy; hot, fair and windy; hot, fair, and quiet; moderate and rainy; moderate, fair, and windy; moderate, fair, and quiet; cool and rainy; cool, fair, and windy; cool, fair, and quiet.* The study shows a marked difference between the sequence of types on the east and west coasts of the continent, while island climate of Habana differs from either coast. It also indicates the lack of dependence upon the average of rainfall to give a conception of the actual moisture conditions. The low latitude of the Canal Zone is characterized by heavy rainfall, but a marked difference is noted on the east and west sides of the isthmus. Colon has an average of 229 hot, rainy days each year, with no marked dry season, while Balboa Heights has but 155 hot, rainy days with a pronounced minimum from December to April. Colon has each year a fifty-day rainy period, interrupted by only an occasional single • Average temperatures for the day of 68° F. or above are called hot, temperatures between 50° and 68° F. are "moderate," between 32° and 50° are "cool." "Rainy days" have over .01 inch precipitation. Windy days have a wind velocity of over 25 miles for a five minute period. fair day. Balboa Heights, on the other hand, scarcely has a twenty-day rainy period that is not interrupted by at least two successive fair days, and one or two single fair days. The first three months of the year are as dominantly fair at Balboa Heights as they are rainy at Colon. The west coast is noticeably more windy than the east coast and also has a preceptibly smaller rainfall. Salina Cruz and Manzanillo have almost constant fair weather from November to May, characterized at Salina Cruz by much windy weather, and at Manzanillo by less wind but occasional moderate temperatures. Vera Cruz has hot, fair, and quiet days from December to May, but has during the year more hot, rainy days than both Salina Cruz and Manzanillo. Progreso resembles the west coast in its distribution of hot, rainy days, but lacks the windy weather characteristic of that coast. Matamoros, just without the Tropics, has more of the variability of the "Temperate" zone, but has an insufficient number of rainy days to make it a highly productive area. Mexico City illustrates the effect of altitude in the Tropics. Moderate temperatures just as truly dominate here, as do hot temperatures on the coast. Hot days occur only from middle April to middle June, and infrequently even then. During the five-year record no windy days were reported. Moderate rainy days occur 63.5 per cent of the time from May to November. During this time, two or more successive fair days occur an average of only 8.4 times. At Habana, hot, fair, and windy days occur during the winter months similar to those of the west coast types. From June to October, hot, rainy days occur from 29 per cent to 40 per cent of the time. Habana, however, has the greater variety of weather for any given number of weeks than has almost any other station of the group. No one type continues for a long period. That the amount of rainfall for a given station is not an adequate basis for determining the weather conditions is shown by the fact that the rainfall of Mexico City is only about one-third that of Vera Cruz or of Balboa Heights. Yet Mexico City has about the same number of rainy days as Vera Cruz, but Balboa Heights has fifty per cent more rainy days than either of the others. Salina Cruz has a rainfall about fifty per cent greater than Mexico City, but Mexico City has two and onehalf times as many rainy days. Since the development of the Tropics seems to depend upon the ability of white men to dwell and work in that region, it seems proper that a more systematic effort should be put forth to determine just what are the weather conditions he will be called upon to endure in different locations, for the sequence of weather types seem to vary greatly with slight changes in location.—(Author's abstract.) Discussion. Dr. S. S. Visher criticized the use of 0.01 inch of precipitation in 24 hours as a fair criterion of a "rainy day." In numerous instances the rainfall comes at night. In the tropics 0.01 inch is insignificant. Since 0.1 inch of dew may sometimes collect overnight, some so-called "rainy days" may be merely dewy nights. Dr. C. F. Brooks, having been involved in the choice of the criteria on which Mr. Howe's and Dr. Switzer's weather types were founded, replied that while he agreed with Dr. Visher in his contention, the real intent of introducing rainfall into these weather types was to provide the readiest substitute for humidity (and lack of sunshine), factors 1.& -day co-ordinate in importance with temperature and wind velocity in making up the human "cooling power," of any weather condition. Dr. Brooks recognized the necessary inadequacy of these first attempts and als hoped the studies could be pushed farther. a ind and hot Later, Dr. Wellington D. Jones, with Mr. Howe, Dr. Switzer, and Dr. Brooks, discussed in detail the desirability of using the distribution of weather types as criteria for differentiating climates rather than following averages of the different elements, as is now usually the case. In view, however, of the well grounded divisions of the earth into climatic regions after Herbertson (Major Natural Regions) and Köppen (more nd detailed divisions based on vegetation), Dr. Brooks and Mr. Howe favored a summary of weather types found in each of Herbertson's or Köppen's regions rather than a new classification which could not differ essentially from Herbertson's or Köppen's and the introduction of which would probably be confusing rather than helpful. bles the has rea ate (To be continued in the February BULLETIN) CO-OPERATIVE OBSERVERS' DEPARTMENT The Climatological Service of the United States Weather Bureau was established years ago to supplement the regular organization. Here we have upwards of four thousand co-operative observers, for the most part serving without compensation. These men and women are doing a patriotic public work. The value of the Climatological Service is well known to the officials of the Weather Bureau, particularly to those who are on duty at the section centers. The records are used by students of climatology, the various classes of engineers, railroad claim departments, those seeking new locations on account of business or health, and by others too numerous to mention. The Climatological Summaries of the United States by Sections, Nos. 1 to 106, have fulfilled a popular demand for detailed data in condensed form for handy reference. These publications cover the United States thoroughly. In order to secure a climatological service of the best type, it is obvious that we must have an intelligent personnel. Without an intelligent personnel it will suffer. To a certain extent the condition will correct itself by a process of elimination. The poor observer will lose interest and quit, but the efficient one will become more and more interested in his work, especially if encouraged, and will continue on for years. But is it wise to experiment with the appointment of inefficient observers, even though they serve but a brief time? In the Illinois Section we have had very satisfactory results in recent years in the selection of co-operative observers. Particular attention has been given to having the applicant properly recommended and ascertaining his age and occupation, and to finding out something about the place available for the exposure of the instruments. If the representatives of the Weather Bureau are persons of some standing in the community, the Bureau gains a certain amount of prestige thereby. During the year 1923 observations were lost for only one month at a single station, and a similar record was made in 1922. We have twenty-seven observers who have served more than ten years, ten whose length of service exceeds twenty years, and two with more than thirty years to their credit. The most unusual record within the writer's knowledge is that made by Mr. John West James, at Riley, McHenry County, Illinois. Mr. James began his record in October, 1860, and continued it until within a few days of his death in the autumn of 1917. This represents a space of fifty-seven years of most excellent service. During that period not a single month's record is missing. Still more interesting is the fact that the entire series of observations was made on the same farm, and probably without change of location. A section director can do much to encourage his co-operative observers. He should establish friendly and more or less personal relations with them, and should be interested in their work. When it is considered that the keeping of weather records is only a secondary matter with most of the observers and that they must give their main attention to making a living, it is truly remarkable the high class of records that are secured from many of the stations. The writer was much impressed during recent inspection trips with the class of men and women who represent the Weather Bureau as cooperative observers. Many of them are representative citizens in their communities, and nearly all are making an earnest and conscientious effort to render the very best of service in making the observations and preparing the reports.-Clarence J. Root, Springfield, Ill. A simple wind vane Make a cone of some light cloth, with an eight-inch opening at one end, tapering to four at the other. Keep the ends open by inserting wire hoops of the proper size in the ends and keep them separated by means of a stiff wire, linking the two hoops. To the large end, attach three wires of stiff iron and bring together at a common point about six inches from large end of cone. Erect a pole at a convenient, good exposure to the wind and affix horizontal arms giving the true North, East, South and West. On top of the pole, place the axle and one wheel of a roller skate, preferably ball bearing, and put an eye in the rim of the wheel. To this eye, attach the already prepared cone. This cone will be found to indicate even rather light winds.-Berne P. Hughes, Co-operative Observer, Monmouth, Illinois. COMMERCIAL USES MADE OF WEATHER FORECASTS At Denver, as in most of the other large cities of the country, the forecasts issued by the Weather Bureau are used principally by dealers in and shippers of fruit, vegetables, bottled goods, etc., and by railroads. Among the most important uses made of the predictions may be mentioned the following: Shippers pack goods to withstand the degree of cold indicated in the forecast. Shipments are delayed if especially damaging temperatures are imminent or are hurried forward if their destination can be reached before the temperature drops. Perishable goods are put on the market immediately if protracted damaging temperatures are indicated. Dealers in table waters and specially prepared drinks prepare for heavy sales when mild or warm weather is forecast, |