ON AMBER VARNISH AND ACID. 227 



\ 



objections will be made to these springs on account of there 

 being so noany joints ; but as there must be either the rub 

 of the spring up and down the back of the pallet, or a dou- 

 ble joint : the latter method is certainly preferable to the 

 former. 



In Mr. Mudge's watches, the adjusting of his auxiliary Defect in. 

 spring to prevent tripping was one reason, why they fre- fudge's. 

 quently stopped ; for when clean, the main spring was ad- 

 justed just to raise up the pallets to their detent, and there- 

 fore,' when the oil got more tenacious, and the works got 

 dirty, the main spring had not power to raise the pallet ; 

 the consequence of which was, the watch stopped. 



The pendulum spring is generally allowed by workmen Pendulum 

 to be the most difficult part of a chronometer to make and sP""g' 

 adjust well. The two back springs answer the purpose of 

 the regulating power, as well as the maintaining power. 



As platina is the closest grained metal we have, and it Preference of 

 can be drawn very hard, 1 prefer stopping the holes with pl^^iua, 

 it. It burnishes very fine, and oil has no chemical action 

 on it. 



If you think these improvement.s worthy a place in your 

 Philosophical J ournal, by inserting them you will oblige 



Your sincere friend, 



DAN. DERING MATHEW. 



XIV. 



Observations on the Possibility of collecting a certain Quan" 

 tity of Succinic Acid, during the Preparation of Amber 

 Varnish, without any Injury to the Quality of the Varnish: 

 by Mr. Planche, of the Society of Apothecaries, Pa- 



JOLAVING had occasion lately to assist in the fabrication succinic acid 

 of a large quantity of amber varnish, I remarked, that snolimesin 

 during the process, and till the heated substance had ac- "Ornish.. 



♦ Annalas d«; Chimie, vol. XLIX, p. 40. 



Q 2 quired 



