Genoa
units of mass

The metric system was adopted in 1845 (Ordinance of 11 September 1845 and law of 25 November 1846) and was compulsory beginning 1 March 1857.

Peso grosso (Heavy weight)

     

pesata (per le legna da fusco*)

           

cantaro

5

         

rubbo

6

30

       

rotolo

16 2/3

100

500

     

libbra

25

150

750

 

oncia or dramma

12

18

300

1800

9000

 

ottavo

8

96

144

2400

14,400

72,000

Doursther (1840)

348.65

522.99

8.72

52.30

261.5

Martini (1883)

3.309
g

26.472
g

317.664
g

476.496
g

7.9416
kg

47.6496
kg

238.248
kg

*The peseta per le legna da fusco is a weight used for firewood. In the port of Genoa it was 4 cantari instead of 5, about 190.5984 kilograms, which is the value given in the official 1877 tables. Doursther (page 400) says this unit was itself called the peso grosso.

Some sources (e.g., Kruse, Doursther) say peso grosso was 110% of peso sottile, that is, 1 cantaro alla grosso = 110 rotoli alla ottile. But others (e.g., Martini) do not agree.

Peso grosso was used for customs, in weighing goods in bulk. Rocca remarks that it was also called peso del ferro.

Peso sottile (light weight)

It was used for goods sold at retail in small quantities, and for  haberdashery, liquor, confections, pharmaceuticals and jewelry. Its libbra is the basis of the weight systems for pharmaceuticals and precious metals.

               

cantaro

             

rubbo

6

           

rotolo

16 2/3

100

         

libbra

25

150

       

oncia

12

18

300

1800

     

ottavo

8

96

144

2400

14,400

   

denaro

3

24

288

432

7200

43,200

 

grano

24

72

576

6912

10,368

172,800

1,036,800

Doursther (1840)

316.693

475.44

7.92

47.55

Martini (1883)

46
mg

1.100
g

3.299
g

26.396
g

316.750
g*

475.125
g

7.91879
kg

47.5125
kg

 

*Kelly remarks, "This weight is variously computed by different authors. Kruse makes it 4903 English grains [317.7099 g]; and Ricard, 4898 [317.386 g]; but the verified standard Pound lately received from James Sterling, Esq. his Majesty's Consul at Genoa, has been found at the London Mint to weigh only 4891½ English grains [316.964 g], as above, which corresponds more nearly with Tillet and Bonneville, who make it equal to 4894 English grains {317.126 g].

The Genoese peso sottile (or peso scarso) system of weights was used in a number of other cities, including Bobbio, Oneglia (present-day Imperia), San Remo and Savona.

 

For Gold, Silver
       

libbra

     

oncia

12

   

quarta

4

48

 

carato*

36

144

1728

grano

4

144

576

6912

45.826
mg

183.304
mg

6.599
g

26.396
g

316.750
g

*This carato, a unit of mass, should not be confused with the carato used in Genoa to say how pure gold was. The fineness of gold was expressed as a part of 24 carati, each of 8 ottavi. So, for example, pure gold is 24carati, and 15 caratai 4 ottavi gold is 64.6% gold. For silver the corresponding terms are 12 once, each of 24 denari. So 8 once 6 denari silver would be 68.75% silver.

Apothecaries'
       

libbra

     

oncia

12

   

dramma

8

96

 

scrupulo

3

24

288

grano

24

72

576

6912

45.826
mg

1.0998
g

3.299
g

26.396
g

316.750
g

For silk
     

libbra

   

oncia

12

 

quarto

4

48

sediceno

4

16

192

1.650
g

6.599
g

26.3958
g

316.750
g

Customs weight

Kruse (1781) describes a rotolo used for customs which, following his equivalents, would have been about 544.27 g.

Peso di cassa

Kruse describes a rotolo peso di cassa, used for weighing Spanish dollars and other coins. Again following his equivalents, about 494.29 grams. 110 of these rotoli equal 100 of the customs rotolo.

Cantaro weight

Finally, Kruse indicates there existed a weight system with the subdivisions the same as the peso sottile, but used to weigh raw or coarse goods. Its most surprising feature is that its rotolo is equal to the Pfund of Hamburg, that is, it would be about 484.4 grams. 102 of these rotoli are said to equal 100 of the rotolo peso di cassa.

woodcut of Genoa

Liber Chronicarum, 1493 courtesy historic-cities.huji.ac.il

Genoa, from a 15th century woodcut.

X

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