A quick search took me to this page: OrderBy Element (Query)
<OrderBy>
<FieldRef Name="Newcomers"/>
<FieldRef Name="Years" Ascending="FALSE"/>
<FieldRef Name="Location"/>
</OrderBy>
All I can say is that you're doing what the documentation shows. Have a poke around over there yourself - I can safely say you have more experience than I do with SharePoint Services.
Edit: I doubt this makes a difference, but try defining your query like this:
var query = '<Query><OrderBy><FieldRef Name="Number" Ascending="TRUE" /><FieldRef Name="Number" Ascending="TRUE" /></OrderBy></Query>';
I just swapped the apostrophe string declaration around to use double quotes, and the case of true
to TRUE
.