Appendix V. 



REPORT ON THE WORK OF THE ASTROPHYSICAL OBSERVATORY FOR 

 THE YEAR ENDING JUNE 30, 1898. 



Sir: I have the honor to submit the report of the Astrophysical Observatory for 

 the year ending June 30, 1898. 



Iu response to your request that the report shall begin with the following state- 

 ments : 



1. The amount, kinds, and classes of property belonging to the Observatory. 



2. The amount of such property acquired during the twelve months covered by 

 the report. 



3. The extent and kind of improvements made in the building and grounds dining 

 the past year, and the estimated cost. 



4. The extent and character of the losses of property, and the origin and causes. 



I have the honor to report : 



Estimated 

 cost to 

 replace. 



(a) Amount and kinds of property in possession of the Observatory July 1, 



1898: 



Buildings. — These include the main observatory building and a smaller 

 photographic room, with their inclosures and appurtenances, such as 

 connecting platform, battery shed, siderostat house, etc $4, 000 



Appliances of buildings. — Consisting of steam-heating plant, refrigerating 

 plant, temperature-control system, and storage battery for general 

 purposes 1 3, 500 



Apparatus for research. — Including siderostat, telescopes, spectroscopes, 

 mirrors, lenses, galvanometers, bolometers, chronographs, clocks, micro- 

 scope, comparator, and many other pieces 21, 000 



Tools and stock in shop. — Including lathes, planer, rolls, motor, and small 

 tools and stock 1, 700 



Books, dratvings, and records. — Iucludingsets of periodicals, maps, drawings 

 of apparatus, books of reference and record, photographic plates 5, 0C0 



Total 35,200 



(&) Within the period covered by the report there has been acquired of the 



various kinds of property above enumerated to the amount of 4, 000 



(c) Improvements to the building were made, including repainting and 



repairs to the extent of 300 



(d) Losses suffered were trivial, and consisted in the breakage of apparatus 



by accident to the extent of 30 



The most important features of the work of the Astrophysical Observatory during 

 the past year have been as follows : 



1. The instrumental equipment has received valuable accessions, including a highly 

 sensitive galvanometer, designed and constructed at the Observatory; twocylindric 

 mirrors by Brashear (which, as used for collimation of the spectroscope, are equiva- 

 lent to a lens of 64 meters focal leugth), and, finally and most important of all, a 

 system of cooling by the expansion of ammonia, which has made possible an exten- 

 sion of constant temperature conditions to cover the five months of March, April, 



69 



