134 Prof. Maskelyne and Dr. Lang's Miner alogicdl Notes. 



line AB reckoned as unity- 

 mark off A/, = n v and the or- 

 dinate fiffi = n ] —m l . In the 

 same way for No. 2 tube, lay 

 off A/ 2 = w 2 and f Q g^=n q — m 2 , 

 which, if a negative quantity, is 

 marked off below AB. The 

 points y„ y 2 , &c. for any num- 

 ber of tubes 1, 2, &c. range in a straight line. Draw perpendi- 

 culars at A and B meeting the line g v # 2 , &c. in D and C. It 

 may be proved that (the expansion of glass being allowed for) 



AD 



-r-jy= difference of vapour- density at upper and lower tempera- 

 ture in terms of the density of the liquid at lower temperature 



A B — B C 

 considered as unity. Also -r-^ — = density cf the liquid at 



the upper temperature in the same terms. 



The curves of the readings of several such tubes about 4 inches 

 long provide the ordinate/^ ; and if extended to sufficiently high 

 terms, afford data to compute the chart-line independently of 

 boiling-point or any observation of tension. A perfectly unknown 

 liquid treated in this way may be established on the chart. 



(See observations on the density of vapours and their liquids 

 at the point of transition, British Association Report, 1853. 

 Also paper in Royal Society's Archives for 1853.) 



XVI. Miner alogical Notes. By Professor N. S. Maskelyne 

 and Dr. Viktor von Lang, of the British Museum. 



[Continued from vol. xxv. p. 453.] 

 Notices of Aerolites. By Nevil Story Maskelyne. 



20. Khiragurh. 



IN the article numbered 14 of these notices, I have given a 

 description of an aerolite that fell on March 28, 1860, at a 

 place called in the description Kheragur, and which I have 

 assumed to be an erroneous spelling of the word Dhenagur. I 

 have to thank Dr. Forbes Watson and Mr. Walker for the infor- 

 mation that there is a place called Khiragurh, some 28 miles 

 south-east of Bhurtpoor, lat. 26° 56' 30", long. 77° 53'. Khira- 

 gurh therefore is without doubt the locality of the fall, and repre- 

 sents the orthography of its name. I trust it may not be long 

 before I may be able to add some facts about the circumstances 

 associated with so recent an event. 



