While today wasn't quite the unabashedly bullish scene we've gotten used to in the past few weeks, blue chips still continued their remarkable rise on Monday. By day's end, the Dow Jones Industrial Average (DJINDICES:^DJI) had added 3 points, or 0.02%, to close at 14,450.

Shares of pharma mainstay Merck (NYSE:MRK) soared 3.2% Tuesday after an independent panel of medical experts gave the go-ahead for the company to continue a trial of its cholesterol drug, Vytorin. Investors cheered the news, though they continue to wait for the final conclusion of the panel, which announces by September 2014 if name-brand Vytorin works better than the cheaper, less profitable Zocor.

A day after weak industrial data from China, Caterpillar (NYSE:CAT) shed 1.6% as shares finished the day as the worst performers in the index. Although the 9.9% production increase in the first two quarters of the year sounds rapid by U.S. economic standards, that's apparently small potatoes for the Asian economy. In fact, the jump in production was the lowest advance the country had seen since 2009. Not good news for Caterpillar's overseas growth prospects. 

Stepping outside the Dow, an increased estimate for first-quarter performance by consumer-technology company iRobot (NASDAQ:IRBT) sent the stock through the roof, as it climbed 5.2%. Take note, Corporate America: Wall Street rarely punishes you when you bump quarterly earnings per share estimates from $0.07 to the $0.16-$0.20 range.

J.C. Penney (NYSE:JCP) added 4% on rumors that its unpopular CEO, Ron Johnson, will be departing. Stock in the retailer remained in positive territory even after the company denied reports that he will leave. With sales taking a nearly 25% hit in the past fiscal year, you can't blame investors for getting a little giddy over the prospects of a major management change. 

Fool contributor John Divine owns shares of Apple. You can follow him on Twitter, @divinebizkid, and on Motley Fool CAPS, @TMFDivine.

The Motley Fool recommends Apple and iRobot and owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.