176 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1919. 
tional field. But the observation is of such interest that it will prob- 
ably be considered desirable to repeat it at future eclipses. The 
unusually favorable conditions of the 1919 eclipse will not recur, and 
it will be necessary to photograph fainter stars, and these will prob- 
ably be at.a greater distance from the sun. This can be done’ with 
such telescopes as the astrographic, with the object glass stopped 
down to 8 inches, if photographs of the same high quality are ob- 
tained as in regular stellar work. It will probably be best to discard 
the use of cclostat mirrors. These are of great convenience for 
photographs of the corona and, spectroscopic observations, but for 
work of precision of the high order required, it is undesirable to in- 
troduce complications, which can be avoided, into the optical train. 
It would seem that some form of equatorial mounting (such as that 
employed in the eclipse expeditions of the Lick Observatory) is de- 
sirable. 
In conclusion, it is a pleasure to record the great assistance given 
to the expeditions from many quarters. Reference has been made in 
the course of the paper to some of these. Especial thanks are due to 
the Brazilian Government for the hospitality and facilities accorded 
to the observers in Sobral. They were made guests of the Govern- 
ment, who provided them with transport, accommodation, and labor. 
Doctor Morize, director'of the Rio Observatory, acting on behalf of 
the Brazilian Government, made most complete arrangements for the 
expedition, and in this way contributed materially to its success. 
On behalf of the Principe expedition, special thanks are due to 
Sr. Jeronymo Carneiro, who most hospitably entertained the ob- 
servers and provided for all their requirements, and to Sr. Atalaya, 
whose help and friendship were of the greatest service to the observ- 
ers in their isolated station. 
We gratefully acknowledge the loan for more than six months of 
the astrographic object glass of the Oxford University Observatory. 
We are also indebted to Mr. Bellamy for the check plates he ob- 
tained in January and February. 
Thanks are due to the Royal Irish Academy for the loan of the 
4-inch object glass and 8-inch ccelostat. 
As stated above, the expeditions were arranged by the Joint Per- 
manent Eclipse Committee with a allocated by the Government 
Grant Committee. 
