540 Reviews. [July» 



ment, and other matters of importance in connection with the signing 

 and sealing of contracts. 



Inventions 3 to 5, 33 to 43, 51, and 75 relate to secret corres- 

 pondence. Writing in cipher was much practised during the sixteenth 

 and seventeenth centuries, and we can understand why this was the 

 case when we remember the instability of the times, the absence of all 

 postal regulations, and the consequent necessity of sending letters by 

 messengers, who were constantly exposed to the attacks of highway- 

 men. Several works relating to different modes of secret corres- 

 pondence were printed during the 16 th century; Francis Bacon (' De 

 Augmentis,' lib. vi. cap. 1) describes at length a cipher which he in- 

 vented when a young man. Many of the letters of Charles I., written 

 during the period of the civil war, are in cipher, as also are some of 

 the letters of the Marquis to the King. 



Inventions 81 and 82 relate to the conveyance of letters secretly 

 by concealment in a comb, and in the handle of a knife, fork, or spoon. 



Invention 32 treats of a universal character intelligible in any 

 language. 



Invention 76 is entitled, " How to write in the dark as straight as 

 by day, or candle light." Mr. Dircks suggests that this might be 

 effected by writing on a ground-glass box lid illuminated from beneath. 



Inventions 6, 7, and 52, refer to telegraphy. The first telegraph 

 was invented by JEneas Tacticus, and was for the purpose of enabling 

 two armies acting in concert to communicate with each other at a dis- 

 tance : one or two other forms were invented in the age immediately 

 preceding that of the Marquis, but we have no record of how they were 

 worked. The 52nd invention (" How to signify words and a perfect 

 discourse by jangling of bells of any parish church ") brings to our 

 mind Sir Charles Bright's recently-invented bell-telegraph, an instru- 

 ment of such efficacy that forty words may be transmitted in a minute : 

 the bells are struck by weighted magnetic needles. 



Inventions 9 to 15, 65, 93, and 96 relate to naval affairs, chiefly in 

 connection with naval warfare. In the annotations to the 15th inven- 

 tion ("A way how to make a boat work itself against wind and 

 tide"), Mr. Dircks has given an interesting historical account of the 

 introduction of paddle-wheels, from which we learn that in an Italian 

 MS., attributed to the fifteenth century, a sketch is given of a boat 

 furnished with two paddle-wheels, fixed on a large vertical wheel, 

 turned by the hand. Further, in 1521, an engraving was published of a 

 vessel provided with paddles, worked by animal power ; and again, in 

 1574, 1578, and 1651 we have notice of similar schemes, so that the 

 Marquis had abundance of previous matter to help him. 



Inventions 8, 24, 28 to 31, 44, 49, 50, 58 to 64, 66 to 68, 73, 80, 

 94, and 95 refer to gunnery, the construction of fortifications, and 

 other matters relative to military affairs. As prominent among these 

 we may mention a " key pistol," which may be used either for unlock- 

 ing a door, or for piercing a breastplate, as occasion may require ; a 

 method of causing a pistol to discharge a dozen times with one loading ; 

 a ready way of loading musketoons on horseback ; and a method of 

 rapidly constructing a cannon-proof fortification. 



