to those employed in biometry to represent the continuous 

 variations, that is to say, polygons of frequency or variation. 



The polygons of frequency have been drawn so that the 

 frequencies represent the percentage of the different classes 

 per hundred or per thousand. 



The author also describes briefly the regions where the 

 cottons which he has investigated are produced and the culti- 

 vation experiments which have been made. He indicates the 

 quotation obtained by each sample examined. 



The author gives, in a schedule, statistics relating to the 

 export of cotton, the cultivated area under cotton, and the 

 average production per hectare. 



The legislation relating to the encouragement of the produc- 

 tion of cotton in the Portuguese Colonies is found at the end 

 of the paper, which is illustrated by several photographs repre- 

 senting* cotton plantations and unginned cottons and twenty- 

 two polygons of frequency. 



The PRESIDENT : The subject which Professor Geraldes has 

 brought to our notice is one which everyone who wishes to see 

 the cotton cultivation of the world extended should read. I am 

 sure we shall read it and think over it, because it raises many 

 important questions. He has, of course, only been able to 

 give us a short summary of the elaborate and valuable paper 

 which he has prepared for the Congress. 



GLI ASPETTI BELLA COTONICOLTURA BELL'ERITREA. 



Per Dott. GUIDO MANGANO. 1 



[ABSTRACT.] 



La cotonicoltura assume niell'Eritrea tre forme ben distinte 

 fra loro, ciascuna delle quali si svolge in una regione a se, e 

 porta ad organizzazione tecnica ed economica completamente 

 diversa. I tre tipi sono particolarmente determinati dall' 

 origine delle acque di cui si vale la coltivazione; dimodoche 

 si hanno colture che possono farsi con le sole acque di pioggia 

 o con le sole alluvioni dei torrenti, opportunamente regolate, 

 o con le pioggie e gli inondamenti insieme. La coltura bene- 

 ficata dalle sole pioggie deve limitarsi a quelle zone che per 

 il loro rilievo o per la lontananza da corsi di acqua non possono 

 consentire la grande coltura irrigua in nessuna delle sue 

 forme. Tali zone sono quelle del mezzopiano sud-occi- 

 dentale e, in parte, quelle del bassopiano verso i fiumi Gasc 

 e Setit. Le varieta di cotone che possono esservi coltivate 

 sono quelle a breve ciclo o quelle a tipo legnoso perenne. 



1 Read by Dr. Oberto Manetti. 



