I have seen examples of how to perform a bulk query on a custom object like this:

sf.bulk.Opportunity.query(
    "SELECT Id, Account.Name, Name, RecordType.Name, Type WHERE Id = 12345")

I have successfully completed queries like this on standard objects. But what I'm looking to do is query a custom object. I'm getting empty responses when I attempt this:

sf.bulk.Custom__c.query(
        "Date__c, ID__c, Transactions__c, Volume__c FROM Custom__c"))

Thanks in advance for any assistance