7S 



MOON IN PLANO. 



long promised to the scientific world : and the first engraving 

 is now offered for their inspection. The whole will be incom- 

 parably the most complete lunar work ever. offered in any age 

 — a work, the more carefully it h examined, either as to its 

 accuracy or elegance (effected indeed, hy extreme labour during 

 twenty-one years), the more it will excite the wonder and ad« 

 miration of the diligent inquirer. 



The utility of these engravings is best expressed in the 

 author's own words ; " The principal use of the moon to as- 

 " tronomers, is, that of ascertaining the longitude of places 

 " by the transit ofthe earth's shadow, when the moon iseclipsed. 

 " The shadow ofthe earth coming in contact with many known 

 " spots, if the observation be made in different places at the 

 " sametim«, the longiaude of each place could by this means 

 " be ascertained with great precision, provided the spots to be 

 " made choice of be sufficiently represented and recogHised.: 

 " but there being no faithful delineation of the moon, 

 " and the edges of those spots which are known being undefi- 

 " ned, the observations made have not been so useful as 

 " could be wished : for this purpose, it is believed, Mr. 

 " Russell's labours will be found very useful, and will very 

 " much add to the certainty and precision ofthe observations 

 *' on Lunar elipses ; as the chief design of his planisphere, 

 " representing the moon in a state of opposition to the sun, 

 " is directed to this end, and which he has spared no pains in 

 " bringing to perfection." 



These engravings, it is expected, will not only prove of great 

 utility to the astronomer, but lead to very important specula- 

 tions in natural philosophy. The remarkable changes of forms 

 in various eminences, the different radiations of light observable 

 at one age of the moon and not at another, with its numerous 

 surprising phenomena, are in these plates faithfully and fully 

 expressed, so as to form a work, it is presumed, highly inte- 

 resting in the departments either of Astronomy or Natural 

 Philosophy. 



CONDITIONS. 



1. The diameter.ofeacli Planisphere is fifteen Inc:hes. — 2. The 

 impressions shall be delivere.l in the order of subscribing. — 3. 

 The price to subscribers for the work is five guineas : an ad- 

 vance will be ma^e to non-subscribers, when the whole has 

 been completed,. — 4 One half ofthe above sum to be paid 



