57 
been sent to India. As soon as it became clear to me that 
it would be extremely diffieult to obtain the necessary funds 
for building an obserfatory, I suggested to Government the 
idea of renting a house at Batavia and adapting this to a 
temporary observatory. I succeeded in obtaining a house 
extremely well situated for the purpose, in which I could 
commence, on January 1* 1866, hourly meteorological and 
magnetical observations with a staff of Javanese assistants 
who had been trained by myself to good observers and computers. 
The system of hourly observations, I then began, has been 
continued without interruption during thirteen years. 
In 1871 I published à volume containing the observations 
made at the temporary observatory in the years 1866, 1867 
and 1868. Now I present to the public two other volu- 
mes containing the observations made from 1869 to 1875. 
Next year I hope to publish the last three vears of obser- 
vations made on the system introduced at the temporary 
observatory. This system will be replaced in 1879 by that 
of the newly built observatory, principally based on the use 
of photographically and other self-recording instruments and 
which I have no doubt will prove far superior to the old 
system , especially for magnetical observations. 
The principle on which the Batavia Observatory was to 
be organized, being still a matter of discussion for Govern- 
ment when I published my first volume of observations, I 
thought it better then not to enter into any details concern- 
ing it. Now, however. the question having been decided; 
and the Observatory having been built, I feel at liberty to 
say a few words about its history. At the same time I 
wish to fulfil now a duty which I bave been obliged to 
defer too long, the duty of expressing my most hearty thanks 
to all those who have assisted in any way in the founda- 
tion of the Batavia Observatory: — to the Royal Academy 
of Sciences at Amsterdam, who so effectually supported 
Vos HumsoLpr’s suggestion; to Professor Buys Barror, the 
