72 REPORTS ON INVESTIGATIONS AND PROJECTS. 



concrete for the enlarged storage battery. This building, 13 by 13 

 feet in size, with cement floor and ventilated roof at the level of the 

 ground, is large enough to contain a storage battery that seems 

 ample for the purposes of the observatory. The number of plates in 

 each of the sixty new cells may be increased from seven, the present 

 number, to fifteen, when more storage capacity is needed. The thirty 

 smaller cells of the former installment are used for special purposes, 

 such as supplying power for the spectroheliograph motors, where 

 great constancy of voltage is necessary to give photographs free from 

 lines or bands due to irregular motion. The Snow telescope-house, 

 laboratories, " Monastery," guest house, and shop are supplied with 

 electric lights. 



Pumping Plant. — The water system was installed during the past 

 summer. A small house built of cement blocks, situated at Strain's 

 Camp, contains a Deaue triplex pump, connected with a 3^ K. W. 

 direct current motor driven by the dynamo at the power-house. 

 The water is raised about 325 feet and carried to a concrete reservoir 

 of 30,000 gallons capacity, situated near the north end of the Snow 

 telescope-house, about 2,100 feet from the well. All the buildings 

 are supplied with water from the reservoir. 



Fire Protection. — The danger from forest fires on Mount Wilson 

 has led me to take special precautions to protect our buildings. 

 During the past summer the Solar Observatory has cooperated with 

 the U. S. Bureau of Forestry in the construction of an extensive 

 system of fire-breaks, guarding Mount Wilson at the most vulner- 

 able points. It is hoped that this system may be extended next 

 year, as it protects both the observatory and the important station 

 of the Bureau of Forestry at Henniger's Flats. In this connection 

 I wish to express our appreciation of the interest in the observatory 

 shown by Mr. Gifford Pinchot, Forester, and by Mr. T. P. Lukens, in 

 charge of the station at Henniger's Flats, under whose supervision 

 the work has been done. I may add that the extensive work of 

 tree-planting on Mount Wilson, so successfully inaugurated by Mr. 

 Lukens, is likely to prove of great future benefit to the observatory. 



A fire-pump, driven by an electric motor, has been established in a 

 small house of cement blocks near the large reservoir. This pump 

 will supply a special fire-extinguishing fluid, or water from the 

 reservoir, to the main system of pipes connected with each building 

 and also to a line of pipes surrounding the Snow telescope-house. 

 Fire hose is available where needed and fire-extinguishers are placed 

 in each building. 



