NATURE 
137 
» THURSDAY, JUNE 19, 1873 
FEREMIAH HORROX* 
Il. 
it is now time to pass to the particular incident which 
has immortalised the name of Horrox, his observa- 
tion of the transit of Venus over the sun’s disc on 
November 24, 1639 (O.S.) It would have been sufficient 
for his renown to have been the first witness of the 
phenomenon, but he had in addition the honour of 
supplying an omission of Kepler’s, who had indeed pre- 
dicted the transit of 1631, but had failed to point out the 
occurrence of another eight years subsequently. The 
transit of 1631 had not been observed owing to its 
occurrence at night, and that of 1639 had been foreseen 
by no one save Horrox, and was watched by no one but 
himself and his friend Crabtree, whom he apprised of the 
forthcoming event in a letter dated on the October 26 
previous. 
We borrow Mr. Whatton’s account of the observation 
(“ Life of Jeremiah Horrox,” pp. 44—46). 
“ After having deliberated on the best method of making 
the observation, he determined to admit the sun’s image 
into a dark room, through a telescope properly adjusted 
for the purpose, instead of receiving it through a hole in 
the shutter merely, as recommended by Kepler. He 
considered that by the latter method the delineation 
would not be so perfect, unless it were taken at a greater 
distance from the aperture than the narrowness of his 
apartment would allow; neither was it likely that the 
diameter of Venus would be so well defined ; whereas his 
telescope, through which he had often observed the solar 
spots, would enable him to ascertain the diameter of the 
planet, and to divide the sun’s limb with considerable 
accuracy. Accordingly, having described a circle of 
about six inches diameter upon a piece of paper, he 
divided its circumference into 360°, and its diameter into 
120 equal parts. .. When the proper time came, he 
adjusted his apparatus so that the image of the sun 
should be transmitted perpendicularly to the paper, and 
exactly fill the circle he had described. From his own 
calculations he had no reason to expect that the transit 
would take place, at the earliest, before three o’clock in 
the afternoon of the 24th, but as it appeared from the 
tables of others that it might occur somewhat sooner, in 
order to avoid the chance of disappointment, he began to 
observe about mid-day on the 23rd. Having continued 
to watch with unremitting care for upwards of four-and- 
twenty hours, excepting during certain intervals of the 
next day when, as he tells us, he was called away by 
business of the highest importance, which could not with 
propriety be neglected, he was at length rewarded for his 
anxiety and trouble by seeing a large dark round spot 
enter upon the disc of light.” 
The “business of the highest importance” was un- 
doubtedly divine service, the transit having taken place 
on a Sunday. Most modern astronomers of Horrox’s 
profession would, no doubt, have considered the 
claims of science paramount onan occasion like this. 
Horrox, in accordance with the feeling of his day, judged 
otherwise, and when all the circumstances of the case are 
taken into account, his sacrifice on behalf of what he 
esteemed a higher duty, must be regarded as an act of 
extraordinary heroism. He had, it is true, almost con- 
vinced himself that the transit could not occur until the 
afternoon, but even this anticipation was a proof of 
* Continued from p. 117- 
No, 190—VOL, VIII. 
courageous reliance on his own judgment, being founded 
on his correction of Kepler’s Rudolphine tables, according 
to the data supplied by which it should have occurred at 
8.8 a.M. The phenomenon was also observed by Crabtree, 
but less perfectly, owing to the cloudy state of the atmo- 
sphere at Manchester. A letter from Crabtree on the 
subject to another north-country astronomer, Gascoigne, 
contains the remarkable expression, “ I do believe there 
are as rare inventions as Galileo’s telescope yet undis- 
covered.” 
Horrox did not remain at Hoole much above six months 
after this great achievement. In July, 1640, we find him 
again at Toxteth, which he never afterwards left. He 
must, accordingly, have resigned his curacy, on what 
account is unknown, as is also the precise nature of his 
subsequent avocations. We only gather from his corre- 
spondence that his affairs were in a very unsettled 
state, that the duration of his stay at Toxteth was 
uncertain, and that he was continually called from home. 
From his complaints of the impossibility of prosecuting 
his astronomical researches, one would almost surmise 
that his occupation was nocturnal, especially as he found 
time for the observations on the tides already referred to. 
His sustained enthusiasm for astronomy, as well as the 
generosity of his temper, is touchingly shown in a letter 
congratulating his friend Crabtree on the success of some 
observations reported by him: “ Your letter alone,” he 
says, “has enough and more than enough to transport 
beyond all bounds a soul more master of itself than mine. 
My emotion and gladness are such as you will more easily 
understand than I express.” After several postpone- 
ments, he eventually fixes January 4, 1641, for a visit to 
Broughton, but the intention was frustrated by his sudden 
death on the morning of the preceding day. We learn 
this from an endorsement by Crabtree, who gives no 
particulars respecting the cause of death, and who him- 
self, according to Dr. Wallis, only survived his friend for 
an extremely short period. 
We are indebted to Crabtree for (the preserva- 
tion of MHorrox’s extant papers, those only having 
escaped destruction which were obtained by him 
after the writer’s death. Of the remainder, part 
were destroyed during the Civil Wars; part carried 
to Ireland by Horrox’s brother Jonas, who appears 
to have shared his scientific tastes, and there lost; 
another portion, after having aided in the compilation of 
Jeremiah Shakerley’s astronomical tables, was destroyed 
in the great fire of 1666. Crabtree’s MSS., happily 
including the autograph of the “Venus in Sole visa,” were 
purchased after his death by Dr. Worthington, of Emma- 
nuel College, subsequently Vicar of Hackney, and a copy 
of the “ Venus,” lent by him to the astronomer Hartlib, 
having found its way into the hands of Hevelius, was 
published by the latter in 1662. The Royal Society, just 
instituted in England, immediately took cognizance of 
the remainder of the MSS., and having obtained these 
from Dr. Worthington, placed them in the hands of Dr. 
Wallis, Professor of Geometry at Oxford, whose Latin 
translation was ultimately published in 1674. By a 
judicious arrangement of his materials he was enabled to 
digest these into a perfect treatise, to which he gave the 
title of “Astronomia Kepleriana Defensa et Promota.” 
To this he added a translation of the scientific portion of 
I 
