1830.] 
Proceedings of Societies. 
355 
tions on the coast. These tables may be copied into a blank leaf of Lalande’s 
small Longitude Tables, and will be found very convenient for reference in that 
form- 
The square of the observed depression in minutes gives the height in feet when refraction 
is i ! 7 . But if refraction be different, the number so found requires a correction: when 
d 2 d 2 d 2 
ref. = d 2 ■+■ ■ 
- = h: ref. = ; d 2 -f- ■ 
= h : ref.: 
= i 1 s ;d 2 + 
- = h: 
5 
11 
25 
d 3 
d a 
d 2 
ref. = d 3 + 
• — h d ~ *4* ' 
= h : 
,p + — 
z=zh: 
6 
14 
37 
d* 
d 2 
d 2 
ref. =r d<x + ' 
■ — h . i si d + 
zzz h : 
I I 5irf' + 
11 
8 
20 
60 
d 2 
ref. = 
= i‘«; d ‘ + 
— h : 
123 
The results so obtained seldom differ more than a few feet from the truth. 
If you think the foregoing worthy a place in your Journal, I shall probably send 
you a few more papers. Some of them on Meteorology, and on the mode of 
finding the dew point from a wet and dry thermometer, which, notwithstanding 
the valuable papers in Nos. 2, 3, and 7, I do not think is yet exhausted. 
Prime numbers have long been an object of interest to Algebraists. I discovered 
the following theorem about ten years ago, and shall feel obliged if any of your 
correspondents can furnish a demonstration . — n being any prime number 2 n — 1 
is a prime. The highest prime generally known at present is 2147483647 = 2 3 1 — 1 
discovered by Euler, and is only a particular case of my formula — 1374389534 71 
= 2 3 " — 1 is a prime much higher than Euler’s j and in this way primes may be 
found to any extent. 
Poona, 1 St/i Sept. 1830. 
VIII. — Proceeding's of Societies . 
1. Asiatic Society. 
Wednesday, the 1 st September. 
Sir Charles Grey, President, in the Chair. 
Captain Benson was elected a Member. A letter was read from the Secretary to 
the Society of Arts, &c. acknowledging the receipt of the 16th volume of the Re- 
searches, and presenting the 47th volume of their Transactions. The following 
donations were received ; viz. The leaf and fruit of the Coco de mer, from Mr. 
Morton. A collection of Fossils, presented through Sir Charles Metcalfe, by Dr. 
Gerard. A work on the Ear, in Hindoostanee, by Mr. Breton. Some Burmese 
Manuscripts, presented on the part of Government. The Pooroos-Purikhya and 
Moral Maxims, translated into English, by Rajah Kalee Krishun, presented by the 
Author. Two pamphlets, presented by the Societd d’Agriculture, &c. of Caen. 
A Grammar of Sanscrit, presented by the Count Malakowski. 
A paper was submitted bv Miss Davy, on criminal punishments, &c. in China. 
A letter was read from Mr. Hodgson, forwarding Catalogues of the Kangyur and 
Tangyur, with remarks, and also one from General Ventura (forwarded by Mr. 
Young) transmitting an account of excavations made by him at Manikyala. 
2. Medical and Physical Society. 
Saturday 7th September. 
A very full meeting of the Medical and Physical Society took place on Saturday 
evening, it being understood that a proposal would be submitted, as to the best 
mode by which the Society could testify their regret for his death, amUheir re- 
spect to the memory, of their lamented Secretary and tellow, Dr. Adam. I he Vice- 
President, Mr. H. H. Wilson, addressed the meeting upon the subject ; and the 
following we believe, is a pretty correct sketch of what he said : 
Before we proceed to the regular business of the evening, I beg to call the 
attention of the meeting to the loss which the Society has sustained in the death 
