VOt. LIII.] PHILOSOPHICAL TRANSACTIONS. 37 



ration, in time, into space ; then in the right-angled triangle sma, fig. 4, or smo, 

 we have given the two sides sa or S6f, and am or cm : therefore the third side sm 

 may be found ; therefore sm the geocentric least distance of the centres is found ; 

 and if to sm we add or subtract the parallax of latitude for the apparent middle 

 of the transit, the sum or difference will be the apparent least distance of the 

 centres. 



Example. To find the apparent least distance of the centres at Tobolsk, 

 The total duration observed at Tobolsk, was 5^ 48™ 53% add Q™ 3' ( = to the 

 effect of the parallaxes of longitude and latitude, both for the ingress and egress, 

 on the supposition that the sun's parallax i3 = 8".5) to this total duration, the sum 

 5^ 55'" 36* is = to the central duration ; consequently 1^ 58"" 38* is = the cen- 

 tral semi -duration, reduce this time into space, and it will be found = to 

 713".956 = AM or aM, and sa or s« ( = difference of the semi-diameters of the 

 sun and Venus) =916'': therefore sm will be found = 571*.37 = the geocen- 

 tric least distance of the centres of the sun and Venus. The parallax of latitude 

 computed on the above supposition of the sun's parallax, for the apparent middle 

 of the transit at Tobolsk, will be found = J 4*. 13, which being added to the geo- 

 centric least distance of the centres above found, the sum 585 '.50 will be the ap- 

 prent least distance of the centres at Tobolsk. 



XL Fill. Of a Case in which Green Hemlock was applied. By Mr. Josiah 



Colebrook, F.R.S. p. 346. 

 Ann James, of the parish of Bough ton Monchelsey in Kent, aged 55 years, a 

 married woman, had for some years complained of a pain and hard lump in each 

 breast. In Sept. J 762 she asked Mr. C.'s advice about them: on examining 

 them, he found a very hard schirrus in each breast : that in the left breast had 

 the mamillary glands indurated and knobbed, like ramifications toward the axilla, 

 a little adhesion to the pectoral muscle, was as large as a turkey's egg, and she 

 was under daily apprehensions that it would break. That in the right breast 

 was not near so large, nor had ramifications, nor adhered like the other. She 

 complained of most excruciating stabbing pains in both breasts, which prevented 

 her having any rest in the night, and made her so very miserable all day, whether 

 she lay down, stood, sat, or walked, that she was unable not only to go out to 

 work, but even to do any thing for her family at home, not even to make her 

 own bed : and she had totally lost her appetite : her usual employ was spinning, 

 washing, brewing, and what in London is called the business of a chairwoman. 

 The breasts were but little discoloured, but the paius she described, and the 

 ramifications attending the schirrus in the left breast, induced him to pronounce 

 it a cancer. 



