1890.] AJdres.^. 79 



out the whole of the region where the observations have been made, 

 the effect being that the plumb-line deviates from the normal to the 

 theoretical spheroid at the stations occupied. Evidence of this kind 

 is gradually being collected which will, when the whole scheme of the 

 Trigonometrical Survey is completed, be all discussed simultaneously, 

 and will without doubt enlarge immensely our knowledge of this 

 abstruse question of local attraction, and may also not improbably lead 

 to some amendment in the adopted elements of the earth's figure. 



Solar Photography. — Tlie two photo-heliographs at the Trigono- 

 metrical Branch Office at Dehra-Dun, one giving eight-inch pictures and 

 the other 12-iuch, have been employed, as usual, during the year in record- 

 ing the spots and faculae visible on the face of the sun. Two negatives 

 have been taken with the smaller instrument on each day that the sun was 

 visible, the larger instrument being only used for recording special 

 phenomena. 656 silver prints of the 8-iuch and 13 of the 12-inch 

 photographs were prepared and despatched to the India Office for com- 

 parison with, and completion of, the Grreenwich observations. The sun- 

 spot minimum still continues and is abnormal in its duration. 



Topographical Surveys. — In addition to the reconnaissance surveys 

 described above, topographical operations have been continued in Balu- 

 chistan, the Himalayas and in the Guiarat district and the South Mahiatta 

 coiintry, Bombay. Forest surveys were carried on in the Hoshungabad 

 and Betul districts, Central Provinces ; the Satara, Nasik, Poona and 

 North Kanara districts, Bombay ; the Madura, Tintievelly and Salem 

 districts, Madras ; and the Prome, Tounghoo, and Thayetmyo districts, 

 Burmah. 



Cadastral Surveys. — Cadastral Survey operations have been con- 

 tinued in the Bilaspur District, Central Provinces; in various Govern- 

 ment and Wards' Estates in Bengal ; in the Tarai, N,-W. Provinces ; 

 in the Nowgong and Sibsagar districts, Assam and in the Thongwa 

 district, Burma. The Cadastral Surveys of Gorakhpur and Basti dis- 

 tricts of the N.-W. Provinces were completed during the year, and new 

 surveys were instituted in the Jalpaigiiri and Chittagong districts and 

 the Burdwan Khas Mehals, Bengal, as well as in the Jhansi district 

 N.-W. Provinces. Traverse surveys were executed by six parties in 

 various districts in the Punjab and Central Provinces. 



The report of the Explorations in Sikkim, Bhutan and Tibet, 

 noticed in last year's address, has been published and contains the 

 detailed accounts of the journeys of five explorers : — 



(1). An account of the Lower Tsangpo, by the Mongolian Lama 

 Serap Gyatsho, 1856-68. 



(2). Narrative of a journey from Darjiling to Gyala Sindong, 

 Tsari, and the Lower Tsangpo, ))y K. P-, in 1880-84. 



