Highlights of the History of the Blue Hill Observatory and the Early Days of the American Meteorological Society 1. Introduction The Blue Hill Meteorological Observatory will celebrate its 100th Anniversary on 1 February 1985.2 The present article highlights historical events, with em- phasis on the Observatory's role in the development of the American Meteorological Society while it was headquar- tered at Blue Hill.3 2. Abbott Lawrence Rotch—founder The Observatory was conceived and constructed by Abbott Lawrence Rotch when he was 25 years old. This fascinating man, born in 1861, was the seventh child of a prominent Bos- ton family which had acquired its wealth in the whaling and FIG. 1. Blue Hill Observatory, circa 1885. A weather flag flies from shipping industries. As a youth, Rotch traveled extensively in the highest mast. A survey marker stands to the right of the tower. Europe with his family and was enrolled in schools in Paris, Berlin, and Florence where he learned to speak French and German fluently. He quickly consulted on the matter with Professor Upton, Rotch's first interest in weather is not known but a small who taught mathematics, meteorology, and astronomy at diary of the weather, which he began in 1878 at "Rear of 3 Brown University, and Reverend Teele, a local minister and Commonwealth Avenue, Boston, Massachusetts," reveals surveyor. Both men thought the idea worthwhile and offered that he was a proficient observer. He graduated from the suggestions. He purchased land, improved a mile-long road Massachusetts Institute of Technology (MIT) as a mechani- up the hill, and constructed a small stone observatory (Fig. 1) cal engineer in 1884, but he had already decided not to pursue at a cost of $3,500. the field of engineering. His family owned a summer home in At midnight on 31 January 1885, fireworks were set off, suburban Milton, adjacent to the Blue Hills. From there he and Rotch commenced a weather observational program often walked in these wooded hills, which formed a west- that has continued uninterrupted. southwest/east-northeast ridge about 16 km south of Boston center city. They also inspired him, according to his diary on 5 August 1884, to erect an Observatory on the highest hill, Great Blue Hill, which is 194 m above sea level. There, he 3. Work under Director Rotch reasoned, he could obtain weather observations free of the disturbing influences found around his Boston home and a. The first year even around the official observing station of the Signal Serv- In addition to the routine weather observations Rotch un- ice in Boston. successfully attempted to have performed by Signal Service personnel, he stated that initial studies would be of changes in precipitation and wind with height. He was encouraged to record the weather elements on open-scale charts, which was 1 15 Nobel Rd., Dedham, MA 02026. not the practice of the Signal Service at the time. Annual trips 2 A comprehensive history of the Observatory is in preparation by to Europe soon provided the best complement of recording the author for future publication. It includes a bibliography of over instruments in the western hemisphere. 1100 books, pamphlets, papers, and climatic summaries prepared by The first year of the operation was fraught with endless dif- staff members. ficulties ranging from leaks in the walls, freezing indoor 3 A similar summary article exclusive of the AMS activities is temperatures, and frequent instrument failures due to the se- scheduled to appear in the December 1984 issue of Weatherwise. vere weather on the barren, windswept hilltop. All of these © 1985 American Meteorological Society events, as well as the weather of each day, were meticulously 30 Vol. 66, No. I, January 1985 Unauthenticated | Downloaded 10/10/21 09:53 PM UTC Bulletin American Meteorological Society 31 recorded in the hand of Willard P. Gerrish, observer for the first year. Rotch soon became world-renowned in the field of meteor- ology as he met with European and American meteorologists and embarked on the systematic acquisition of meteorolog- ical books and data. The Observatory was informally asso- ciated with the Harvard Astronomical Observatory from the beginning and by 1889, under a financial agreement, Har- vard took over publication of the research papers and obser- vations beginning in 1887. b. Early cloud statistics Henry Helm Clayton, age 24, arrived from the University of Michigan in 1886 to replace Gerrish. Clayton was already in- terested in clouds and soon started recording their amount and type each hour. He was also interested in forecasting and modifying the Signal Service forecasts that Rotch arranged to receive by telephone and broadcast by means of "weather flags" from the tower. A year later Clayton brought Sterling P. Fergusson, age 19, to the hill. Fergusson was a mechanical genius and soon had the instrumental problems under con- trol. Clayton and Fergusson, under the guidance of Rotch, FIG. 2a. Composite model of cloud types around a cyclone cen- tered at ©; C, CS, AS, AK, N, and SK indicate cirrus, cirrostratus, made an excellent team. Rotch circulated internationally, altostratus, altocumulus, nimbus, and stratocumulus, respectively. was current in research, and supplied the administration and funds. Clayton also came forth with new ideas and per- formed most of the analysis while Fergusson developed and maintained the necessary instrumentation in the Observa- tory shop. By 1890, the first detailed cloud statistics in America were being accumulated to show cloud types and amounts, and their diurnal and seasonal variations. c. The measurement of cloud heights and their velocity FIG. 2b. Southwest-northeast cross section through the cloud Cloud observations were emphasized in the belief that model. The cirrus was placed at 9 km. further understanding would improve the forecasts. In 1890, two Mohn cloud theodolites were set up and connected by telephone to triangulate on clouds. Similar work was already in progress at Uppsala, Sweden. Fergusson made a pair of small-scale theodolites from which observed lines of sight to a cloud were duplicated by threads. This model eliminated laborious calculations in finding the point where the two lines of sight came nearest to each other since, due to errors, they seldom intersected. Successive sightings on the same cloud were used to determine direction and speed of move- ment. These observations provided the first basic climatol- ogy of cloud types, height and velocities in the western hem- isphere. From these data Clayton showed that wind speeds on Blue Hill and Mt. Washington were higher than those in the free air at the same level. Clayton also derived composite wind patterns at all levels up through the cirrus above cy- clones and anticyclones and compared the models with those developed in Europe. In 1896, composite models of cloud forms around a cyclone, Fig. 2a, and along a cross section through a cyclone, Fig. 2b, were published. It is interesting to compare the Blue Hill models with the famous Bjerknes model, Fig. 3, of some 20 years later. Cloud tops near the cy- clone center in Clayton's model were based on a few free bal- loon flights in Europe. These no doubt were made in weather less severe than average; hence, somewhat low but not unlike FIG. 3. The famous Norwegian cloud model around a cylcone, the Bjerknes model. drawn by Jacob Bjerknes. Unauthenticated | Downloaded 10/10/21 09:53 PM UTC 32 Vol 66, No. 1, January 1985 curred, which required a search for the kites and meteoro- graph, and retrieval of long lengths of the restraining wire. Sample plots of soundings are shown in Fig. 5. Wind direc- tions were obtained by sightings on the uppermost kite, and speeds were measured from a small cup anemometer, which was a part of the meteorograph. Details obtained from these soundings were comparable to those obtained today using the best techniques. e. Atmospheric exploration using balloonsondes Rotch was well aware of European experiments in which re- cording instruments were lifted to heights exceeding 10 km by hydrogen-filled balloons, but he could not duplicate these flights at Blue Hill because the instruments would most likely fall in the sea to the east. However, in 1904, he seized upon the opportunity to make similar flights from St. Louis at the Louisiana Purchase Exposition. His good friend de Bort supplied instruments at cost. On 15 September 1904, Fergus- son released the first balloon and meteorograph, which in one hour and 26 minutes ascended to 17 045 m and returned to the ground. A perfect record of temperature and pressure was obtained. Other soundings followed, some from Pitts- field, Mass., and the general characteristics of the tropo- sphere and lower stratosphere were determined and com- pared with those over Europe. f Death of Professor Rotch Rotch died suddenly on 7 April 1912 after an undiagnosed ruptured appendix. Letters of condolence poured in from Europe and America. According to his wishes, the Observa- tory was bequeathed to Harvard with $50,000 to be set up in FIG. 4. First kite-meteorograph with basket radiation shield an endowment fund to operate the facility. The transfer did removed. not take place until 1913. Meanwhile, the financial burden was assumed by Mrs. Rotch. Rotch, who had been made the d. The use of kites for atmospheric exploration first professor of meteorology at Harvard in 1906, was uni- On 4 August 1894, for the first time a series of five kites, made versally recognized for establishing and maintaining the now by William A. Eddy, lifted a specially constructed thermo- famous Observatory. It had developed a unique climatologi- graph off the ground at Blue Hill. This instrument, Fig. 4, cal record and the most complete meteorological library out- weighed 1.1 kg and when sent aloft it was screened from radi- side Washington, D.C.