378 Lieut. Mudge on the Difference between 
tore of the Olive, the spontaneous growth of the Strawberry 
tree, the Pomegranate tree, and the Lavender, speak still more 
plainly to the eye. This change is very perceptible, when, in 
going from Paris to Marseilles, one reaches the territory of 
Montelimart. The borders of the Mediterranean are a little 
warmer ; and species belonging to the Genus Mygale , Oniiis , 
Cebrio , Brenius and Scarites , appear there for the first time. If' 
we penetrate into the interior of Spain, and visit its beautiful 
eastern provinces, where the orange and the palm are vigorous 
in the open air, a new assortment of species, intermingled with 
some already observed in the south of France, will command 
our attention. We may there observe species of the Erodius , 
Sepidium, Zygia , Nenioptera , Galeodes , and many other in- 
sects analogous to those of Barbary and the Levant. The know- 
ledge of these species having become familiar to us, the entomo- 
logy of the Atlantic countries of Africa, or of those which are 
situated on the Mediterranean, as far as the Atlas, will not excite 
in us very great surprise. We shall there, however, discover 
certain genera of insects which have their centre of dominion in 
the regions comprised between the tropics ; such as the Genus 
Anthia , Graphipterus , Siagona, &c. 
We have only a very imperfect knowledge of the insects 
of the south-east of Europe. I shall merely remark that the 
Papilio crysippus of Linnaeus, common in Egypt and the East 
Indies, appears already in the kingdom of Naples. 
{To be concluded in neoct Number.) 
Art. NN. — On the Difference between the Land and Sea 
Rates of Chronometers , deduced from the Register kept on 
board his Majesty's Ship Leven , in two Voyages to the Cape 
de Verd Islands. By Lieutenant Mudge, R. N. 
t INDING, on my return from a recent voyage to the Cape 
de Verd Islands, that the attention of philosophers has been 
called to the subject of chronometers, and particularly to their 
change of rate on ship-board and on shore ; and having, with 
Lieutenant Vidal, for nearly three years, kept the rate of the 
four chronometers appropriated to this vessel, under different 
