To find the ratio of votes in favor of the law to the votes against the law, we start by determining the total number of votes against the law.
Given that 64 out of 70 votes were in favor, we can find the number of votes against the law by subtracting the votes in favor from the total votes:
\[ \text{Votes against the law} = \text{Total votes} - \text{Votes in favor} = 70 - 64 = 6 \]
Now that we have the number of votes in favor (64) and the number of votes against (6), we can express the ratio of votes in favor to votes against:
\[ \text{Ratio} = \frac{\text{Votes in favor}}{\text{Votes against}} = \frac{64}{6} \]
Next, we simplify this ratio. Both 64 and 6 can be divided by 2:
\[ \frac{64 \div 2}{6 \div 2} = \frac{32}{3} \]
Thus, the ratio of the number of votes in favor of the law to the number of votes against the law is:
\[ \boxed{\frac{32}{3}} \]