Boyd takes additional measurements of the mass of product formed in a reaction. he uses a balance that has smaller graduations than the first balance he used.

what is boyd most likely trying to change?

I think Boyd is most likely trying to change the accuracy of the mass of the product formed in the reaction. He uses smaller graduations in order to really record the exact mass of the product up to the smallest graduation available. Hope this answers the question.

Generally travels west to east but often shifts to north and south