1818.] Scientific Intelligence. 73 



the Niger and Tombuctoo by a new route, which seems indeed 

 to hold out peculiar advantages. The present Bashaw of Tripoli 

 has intimated his readiness to co-operate with the British 

 government in the promotion of their plans ; Fezzan is a depend- 

 ency of Tripoli, and is at this time governed by a Bey, who is 

 the son of the Bashaw ; and it appears that there is a constant 

 communication between Fezzan and Kashna, Bournou, and even 

 Tombuctoo itself. It seems that the French are likewise turning 

 their attention to the same object, and that the traveller Bahdia, 

 who is so well known under his assumed name of Ali Bey, is 

 now entering upon an expedition, which is stated to be nearly 

 the same with that which had been projected by Burckhardt. 



II. On Pargusite. 



(To the Editors of the Annals of Philosophy.) 

 GENTLEMEN, 



The new mineral, of which you have given a short notice in the 

 last number of the Annals under the name of pargusite, has been 

 known in this country three or four years, and was described by 

 the Abbe Haiiy in vol. i. of the " Memoires du Museum d'His- 

 toire Naturellej" published in 1815; he found the crystalline form 

 of many of the grains, and the cleavage, similar to those of horn- 

 blende ; of which mineral he considered it a variety. He says he 

 observed in some of the grains traces of a dihedral summit, and 

 these traces have probably led the author of the description you 

 have copied to regard the form of the substance as an octohe- 

 dron ; a form which would obviously result from a very short 

 prism with the dihedral termination. The relative proportions 

 of the component parts of hornblende differ considerably in the 

 different analyses which have been- published. But the presence 

 of fluoric acid does not appear to have been noticed before. 



I am, Gentlemen, yours, &c. F. J. 



N. B. Has not Capt. Hall mistaken some of the molluscae for 

 polypes in the description you quote of the coral reefs, observed 

 by him near the island of Loo-Choo ? 



III. On Mr. Tritt oil's distilling Apparatus. 



(To the Editors of the Annals of Philosophy.) 

 GENTLEMEN, 

 You have inserted in the last number of the Annals an account 

 of the apparatus contrived by Mr. Tritton for distilling in vacuo; 

 the attempt, although not new, is specious ; and when the 

 method is recommended by so respectable a philosopher as Mr. 

 Allen, it is extremely probable -that it will, to a certain extent, 

 meet with the patronage of the public. I had prepared some 

 remarks to show that the employment of the apparatus in ques- 

 tion must necessarily end in disappointment ; 1 shall, however, 

 content myself with merely sending you for insertion in the 

 Annals the following extract from vol. i. p. 190, of Dr. Black's 



