French National Injlituta 1*9 



and to confine themfclves to a fmall number of families, 

 multiplying the examples in each. They ought, above all^ 

 to infill on the relations and differences of the families di- 

 ftinguiftied by characters of the firft value ; and they mud 

 avoid reducing their labours to compilations from the authors 

 who have written on the fame fubjecl:. 



The prize will be a gold medal of the value of rive hecto- 

 grammes of gold; it will be decreed in the public fitting of 

 Mefudor 15th, year 11, (July 4, 1803). The anfwers will 

 be received till the 1 ft of Germinal, (March 22,) year 11, and 

 not beyond that period. 



Tire Clafs of the Moral and Political Sciences propofed 

 the following queftion : 



To compare the geographical knowledge of Ptolemy, in 

 regard to the interior or Africa, with thofe tranfmitted to us 

 by later geographers and hiftorians, excepting Egypftnd the 

 coafts of Barbary, from Tunis to Morocco. 



The prize will be five hectogrammes of gold (truck into 

 a medal : it will be determined in the fitting of Vende- 

 miaire 15th, year 11, (7th October, 1802). The anfwers 

 will be received till the 15th Mefiidor, year 10, (July 4th), 

 1802), artd not beyond that period. 



General conditions to be obferved by the candidates for 

 the prizes whatever be the fubjecl:. 



No paper tranfmitted in anfwer to the queftions mu ft bear 

 the name of the author, but be diftinguimed only by a de- 

 vice : a fealed note may be attached to it, containing the 

 device, and the name and addrefs of the author. This note 

 will not be opened by the Inftitute except in the cafe of the 

 piece having gained the prize. 



The anfwers may be tranfmitted to the Inftitute, fending; 

 the packet containing it poft paid. They may be addrefl'ed 

 alfo, poft paid, to one of the fecretaries of the Clafs at Paris, 

 or be delivered into his hands: in the la ft cafe, the fecretary 

 will give a receipt for it. The Inftitute informs the compe- 

 titors that it can return no memoirs, drawings, or machines, 

 tranfmitted to them ; but the authors will always be allowed 

 to have copies of the memoirs and drawings, and models of 

 the machines. A commilTion of the Inftitute will deliver the 

 gold medal to the bearer of the receipt; and, in cafe there is 

 no receipt, the medal will not be delivered but into the hands 

 of the author, or fome one properly authorized to receive it. 



The following account of the mathematical labours of the 

 Clafs of the Mathematical and Phyfical Sciences during the 

 third quarter of the year 9, was read by Delambre : 



Memoir on achromatic glajfes^ adapted for the mcafurcment 

 tf angles \ and on the advantages %vhicb may be derived ;?om 



M 2 double 



