W. M. Foote—Leadhillite Pseudomorphs in Missouri. 99 
If these mechanical forces are to be superposed upon gravi- 
tation, then the effect upon the motions of the earth and also 
of the other planets, should be expected, and the suggestion 
herewith made is that the outstanding motions may be due not 
to unknown masses of matter, nor to the modified law of gravi- 
tation, but to certain stresses imposed upon the ether by the 
radiant energy of the Sun. 
The definite problem thus set before magneticians, namely, to 
determine fully the magnetic action of the sun on the earth, 
by means of the vector forces at the surface of the earth, 
should bring about two reforms in the observatory methods 
now in use. 1. The distribution of permanent observatories 
should be made in conformity to the field to be observed. 
2. The type of instruments and the methods of reduction 
should be made uniform. It is very exasperating to employ 
the present heterogeneous material; and often the cause of 
misinterpretation is to be attributed to this divergence among 
the reported observations. The singleness of the main problem 
and the necessity of intelligent codperation, together with the 
great importance of the cosmical physics involved, ought to 
raise magnetism of the sun and the earth into the front rank in 
science. The normal systems of the magnetic and electro- 
magnetic fields evidently become the means of checking the 
performance of the instruments of any observatory, which will 
add much to the precision with which the instruments are 
handled. Also the elimination of the normal system from the 
observed values of the magnetic force, give certain residuals 
which are to be interpreted as forces indicating physical actions 
within the sun, or else in the atmosphere and the shell of 
the earth. In this way many sensitive variations of the traces 
of the photographic magnetograms will in due time find their 
true and useful interpretation for practical purposes. This 
system of measures, delicate to a remarkable degree, will there- 
fore become available for forecasting weather and allied phe- 
nomena. 
Art. 1X.—Wote on the occurrence of Leadhillite Pseudo- 
morphs at Granby, Mo. ;* by WARREN M. Foote. 
AMONG some leadhillite specimens found a year ago in the 
Beer Cellar mine at Granby, Mo., were several examples of a 
mineral replacing calcite. These were preserved by the super- 
* Mention is made of pseudomorphism in Messrs. Pirsson and Wells’ descrip- 
tion of the Granby Leadhillite, this Journal, Sept. 1894, 
