350 Analysis of ' Scientific Books and Memoirs. 



4. Dried Sulphate of Soda. - - 100 



Slacked Lime, - 266 



Sand, ... - 500 



Broken Glass, - - - 50—200 



See the Description, de Brevets, or the Annates de V Industrie National. 



13. Description of an Improved Mortise Lock. Invented by Messrs John 

 and Thomas Smith, Darnick. Plate VI. Fig. 7, 8. 



A is the spring-bolt, cranked inside to avoid the key of the lock bolt, 

 and to bring its nose and tail into the same line. 



B, the tumbler, or follower, of hardened steel, made to work upon the 

 breech CC, which is of brass, and fixed to the bell by the tenor CC. 



E, a piece of brass, with an oblong hole through it, to admit of the tail 

 F working through it, to keep the bolt in its proper place, and diminish 

 the friction. 



The spring G, and player H, are brought to the fore end of lock, which 

 allows it to be narrowed at the other end. 



In the lock-bolt and night-bolt, there is little difference from the com- 

 mon lock. 



The advantages of a lock constructed upon this plan, are the following, 

 viz. 



1st, It is less bulky than the common lock, easier put on, and does not 

 weaken the door so much. 



2d, There is less friction in the working, from the spring being placed 

 to draw, in place of pushing, as in the common lock. The slide at F also 

 contributes much to diminish the friction. 



3d, It works with perfect equality whichever way the handle is turn- 

 ed, from the tumbler being placed exactly in the line of the centre of the 

 bolt ; which it is evident the common lock can never do, from the tum- 

 bler being placed so far from the bolt. In the common lock there is a dif- 

 ference, in most cases, of between 30 and 40 per cent- between the turns of 

 the handle, which is the reason of the bolt coming readily back when the 

 handle is turned the one way, and often sticking fast when turned the 

 other way. 



This we conceive to be the principal advantage of our lock. 



Art. XXVIII— ANALYSIS OF SCIENTIFIC BOOKS AND 



MEMOIRS. 



Deutschland's Flora. By Franc. Carl. Mertens, and W. H. J. 



Koch. 



We shall take the opportunity, whilst we notice the commencement of 

 this long expected work on the Plants of Germany, to offer a few observa- 

 tions on the state of botany in that vast empire, including, as it does, with- 

 in its limits, above 10° of latitude, and 24° of longitude ; bounded by Italy 



