The rise of the factory system extended the use of child labor.  Manufacturers found children as young as 3 years old could collect cotton waste that accumulated near machinery.  Children of 7 years and upwards could be employed to operate simple carding and spinning equipment.

Child wage workers comprised the bulk of Slater's work force when he first started producing yarn in the clothier's shop in Pawtucket, Rhode Island.  Samuel Slater hired four boys between the ages of 7 and 12 years of age to operate the three carding machines, two water frames and one carding and roving machine.  Within three weeks he doubled the number of child laborers hiring girls as well as boys as shown below.  The first record of employees begins December 20, 1790 as follows:
 December 20, 1790:
4 Boys Hired:
Turpin Arnold 
Charles Arnold
Smith Wilkinson
Jabez Jenks
December 27, 1790:
1 Girl Hired:  Eunice Arnold
December 29, 1790:
1 Boy Hired:  Otis Borrows
December 30, 1790:
2 Boys Hired:  John & Sylvanus Jenks
January 3, 1791:
1 Girl Hired:  Ann Arnold
Source:  Father of American Manufacturers

During the week January 3, 1791 all 9 employees (7 boys, 2 girls) worked full time for six days.

All workers were children between 7 and 12 years old.  The character of Slater's workforce was not unusual.   Everywhere Slater encountered the tough Yankee farmer whose distrust of manufacturing stemmed often from personal experience in the sweatshop of those grim factories in England.  It was assumed that work in the factory was perdition itself.  Factory work would bring a loss or rank and grace.  Working in a factory was humiliating to men.  Slater offered them employment as watchmen and construction workers, jobs deemed appropriate for men use to freedom of outside labor.  By providing men with such jobs and by paying them adult male wages, Slater reinforced the male householder's position with the family as primary provider.  Only then did they allow childen to work in the mill.  Children became good help trained in turning out superior yarn supervised by Slater.  These children, performed a wide variety of tasks from picking cotton clean of dirt, leaves, pods and other foreign matter to operating carding and spinning machines.   These young children already accustomed to farm work, helped families by working in mills.  Few families believed they could survive without labor of their children.

Slater recruited children on contract, even when he introduced apprentices.  For years boys and girls under contract shared the workplace with apprentices and labored under similar conditions.

For 12 hours a day in winter and 14 to 16 hours a day in summer, 6 days a week, boys & girls worked in factories.  On Sunday, they marched to Sunday school alongside apprentices in which students from Brown University taught factory children basic reading and writing skills.

From 1794 to the end of the decade pauper apprentices and child workers labored together in the factory.  In an ad published in the Providence Gazette, Slater's decision to employ apprentices to operate some of his equipment appeared as follows:  "4 or 5 active lads, about 15 years of age to serve as apprentice in cotton factory."

The factory became the employer of pauper apprentices.  Slater found the system inflexible, expensive and inefficient.  Slater had to conform to certain guidelines regarding training and education of his apprentices.  Educational services had to be provided.
The following costs were involved in support of an Apprentice in 1796:
Room & Board with family in area: $1.44 - $2.00 weekly ea. apprentice
Medical Bills, clothing, shoes $0.32
Total Costs a week: $1.75 - $2.32 weekly
Total Costs annually: $90 - $120 annually
Source:  Samuel Slater & the Origins of the American Textile Industry

The new improved mill that Slater, Almy and Brown built in 1793, retained the child labor system.  Within 3 years the new mill had more than 30 employees.  Childrens names dominated the roster with several families supplying more than one child.

The need for children expanded as the mill expanded and early recruits and apprentices fled.  As the mill became dependent on children, families became dependent on the mill, which grew to need each other.  This mutual dependence forced Slater to provide services outside the mill.  Slater, Almy & Brown constructed at least two houses for factory families before 1796.  Multiple family dwellings soon followed, an improvement over what housing workers could afford on their own. Slater supplied workers with household needs, deducting rent and purchases from the company store from weekly pay.
In the first decades of the 19th Century, young children, adolescents, boys and girls and unmarried women comprised approximately 3/4 of the industrial workforce.   By 1827, 102 people worked in the factory.

In 1840, 30 children and adolescents worked in the carding department under direction of an overseer.  Two-thirds of the workers were females.

Source:  Samuel Slater & the Origins of the American Textile Industry

Children ages 9-12 made up 52% of the workforce; children ages 13-15 made up 31% of the workforce; and children ages 16+ made up 17% of the workforce in the Carding Department.
In 1840, 25 laborers worked in the Spinning Department:

Source:  Samuel Slater & the Origins of the American Textile Industry

Children ages 8-12 made up 32% of the workforce; children ages 13-15 made up 44% of the workforce; and children ages 16+ made up 24% of the workforce in the Spinning Department.
In 1840, 69 women worked in the Weaving Department:

 Source:  Samuel Slater & the Origins of the American Textile Industry

Out of the 69 women that worked in the Weaving Department in 1840, 67 were ages 14-24 years old.  Only 2 were ages 11-12.