New Publications. 325 
af expreffing all, the poffible variations and combinations. of 
the letters. of the alphabet, forms, in a proper fenfe, the true 
telegraphic art. Even the fignals at fea, as they extend only; 
to particular circumftances, are, when compared to-fignals 
by. letters, only a kind of hieroglyphies, 
. The proper telegraphic art, however, was not unknown 
te the ancients. ‘The Greeks and the Romans, for fignals, 
made ufe of pots filled with lighted twigs and ftraw, over. 
which they poured oil; and thefe being placed in certain 
rows, expreffed certain letters, according to the order in 
which each row was lighted. Polybius mentions a method 
in which the letters of the alphabet were divided into five 
rows; and by means of a certain number of torches, raifed 
on the right and left, the number of the row, and the letters 
in the row, could be expreffed. The /eganograpbia, trithe- 
miana of a benedictine monk, in the 15th century, feems ta 
have been fomething of the fame kind; but the firft experi- 
ment, after the manner of the Greeks, is defcribed by Kir- 
cher in his Ars magna lucis et umbre, under the title of Cryp- 
togamia catoptrica. It was, however, imperfect, and could 
be employed only at acertain diftance. Schott in his Tech- 
nica curiofa propoles, from an anonymous author, ‘to erect 
polts upon an eminence, fo as to be diftinguifhed through a 
4elefeope, and on which proper fignals could be elevated as 
might be neceffary., Kefsler, in his Concealed Arts, advifes 
ehara&ers to be cut out on the bottom of a cafk, fo as to ap- 
pear luminous; and Hook propoies certain figures, the form 
of which could be eafily changed, to be fufpended on a wood- 
en frame. »Gautkey recommends tubes’ fume thoufand fa- 
thoms in leneth; Guyat, tables with the letters cut out‘in 
them ; and Paulian, in his Dictionnaire de Phyfique, a trant= 
parent figure confifting of one perpendicular and three hori-+ 
zontal firipes forming ten compartments, each of which, by. 
removing boards from behind, can be réndered viSble or int 
vifible. The inventions of Linguer, Bergftraffer, ‘Chappe, 
Burja, Bockman, and Achard, were all much on the-fame 
= Y3 plan, 
