Prof. De Morgan on the Syllogism No. IV. 473 
previous year he had seen two new bodies pass before the sun in dif- 
ferent directions and with different velocities. ‘The larger was about 
3" in diameter, and the smaller from 1” to 1°25. Both appeared 
perfectly round. Sometimes the smaller preceded, and at other 
times the larger. The greatest observed interval between them was 
1’ 16": at times they were very near each other. Their passage 
occupied a few hours. Both appeared as black as Mercury on the 
sun, and had a sharp round form, which, however, especially in the 
smaller, was difficult to distinguish.” Schumacher considered it his 
duty as editor to insert the communication, but evidently did not 
give credit to it (Astron. Nachr. No, 273). 
In vol. ii. of the Correspondence between Olbers and Bessel, 
mention is made in p. 162 of an observation at Vienna by Steinhtibel, 
of a dark and well-defined spot of circular form which passed over 
the sun’s diameter in five hours. Olbers, from these data, estimates 
the distance from the sun to be 0°19, and the periodic time thirty 
days. It is remarkable that Stark saw about noon of the same day 
a singular and well-defined circular spot, which was not visible in 
the evening. ‘This is one of the instances in vol. xx. of the Monthly 
Notices of the Astronomical Society. 
These accounts appear to prove that transits of dark round objects 
across the sun are real phenomena; but it would perhaps be prema- 
ture to conclude that they are planetary bodies. If the object ob- 
served by Lescarbault be a planet, it is certainly very surprising that 
it has not been often seen. Schwabe, after observations of the sun’s 
face continued through thirty-three years, has recorded no instance 
of such atransit. It is probable that now attention has been espe- 
cially drawn to the subject, future observations, accompanied by 
measures (of which Lescarbault’s are the first instance), may throw 
light on the nature of these phenomena. 
April 23.—Professor De Morgan read a paper ‘‘ On the Syllogism, 
No. IV., and on the Logic of Relations.” 
In the third paper were presented the elements of a system in 
which only onymatic relations were considered; that is, relations 
which arise out of the mere notion of nomenclature—relations of 
name to name, as names.. The present paper considers relation in 
general. It would hardly be possible to abstract the part of it 
which relates to relation itself, or to the author’s controversy with 
the logicians, who declare all relations material except those which 
are onymatic, to which alone they give the name of formal. Mr. 
De Morgan denies that there is any purely formal proposition except 
“there is the probability a that X is in the relation L to Y;” and 
he maintains that the notion ‘ material’ non suscipit magis et minus ; 
so that the relating copula is as much materialized when for L we 
read identical as when for L we read grandfather. 
Let X..LY signify that X stands in the relation L to Y; and 
X.LY that it does not. Let LM signify the relation compounded 
of L and M, so that X..LMY signifies that X isan L of an M of Y. 
In the doctrine of syllogism, it is necessary to take account of 
