398 Miscellaneous Intelligence. 



of 798 feet in the earth had no sensible influence upon the inclina- 

 tion of the needle. 



11. Use of Muriatic Acid in cleansing Monuments. — The time 

 and expense necessary in cleansing stone buildings and monuments 

 by scraping them, induced M. Chevalier to try other methods. He 

 finds it may be done, i. by dry brushing, but the process has in- 

 convenience ; ii. by washing first with a brush and water, then with 

 water acidified with muriatic acid, and finally by water alone ; iii. 

 by washing with a weak alkaline solution, and then with a very 

 dilute acid. The second process is considered as the most advan- 

 tageous, and has been applied on the walls of the Ecole de Medecine. 

 It is now under trial upon the marble statues of the gardens and 

 halls in the building. 



12. Preservation of Firemen exposed to Flames. — The Chevalier 

 Aldini of Milan has been earnestly occupied in the construction of 

 an apparatus, or rather clothing, intended to preserve persons from 

 injury who are exposed to flames. The apparatus has lately been 

 fully tried at Geneva, and an account of it, and the trials, given in 

 the Bibliotheque Universelle. A union of the powers possessed 

 by a metallic tissue to intercept flame, with the incombustible and 

 badly conducting properties of amianthus, or other substances, has 

 been made in the apparatus ; and the latter consists of two distinct 

 systems of clothing, the one near the body composed of the badly 

 conducting incombustible matter, and the other, or external en- 

 velope, of a metallic tissue. 



The pieces of clothing for the body, arms, and legs, are made of 

 strong cloth which has been soaked in a solution of alum ; those 

 for the head, the hands, and the feet, of cloth of asbestos. That 

 for the head is a large cap, which entirely covers the whole to 

 the neck, and has apertures in it for the eyes, nose, and mouth, 

 these being guarded by a very fine copper-wire gauze. The stock- 

 ings and cap are single, but the gloves are double, for the pur- 

 pose of giving power of handling inflamed or incandescent bodies. 



M. Aldini has, by perseverance, been able to spin and weave 

 asbestos without previously mixing it with other fibrous substances: 

 the action of steam is essential in the bending and twisting of it, 

 otherwise the fibres break. The cloths prepared with it were not 

 of close texture, but loose : the threads were about one-fiftieth of 

 an inch in diameter, and of considerable strength : cords of any 

 size or strength may be prepared from them. M. Aldini hopes 

 to be able so to prepare other fibrous matters, as to be able to 

 dispense altogether with this rare and costly material. 



The metallic defence consists of five principal pieces: a casque, 

 or cap complete, with a mask : this is of such size as to allow of 

 sufficient space between it and the asbestos cap, and is guarded 

 before the face by a visor, so that the protection is doubled in that 



